Статті в журналах: "Narrowband survey"

1

Drew, Janet E. "New and old roles for narrowband Hα". Proceedings of the International Astronomical Union 5, H15 (листопад 2009): 778. http://dx.doi.org/10.1017/s1743921310011567.

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AbstractUntil recently, Hα has been seen as the tracer of ionized gas, picking out both star formation and the late stages of stellar evolution. This has been reaffirmed, spectacularly, by the recent WHAM and SHS surveys. But the advent of large-area digital detectors creates a new role for narrowband Hα as a direct, simultaneous, measure of intrinsic stellar colour and reddening when e.g. r'-Hα is combined with a nearby broad band colour e.g. r'- i'. This new capability has been clearly demonstrated by the nearly-complete IPHAS survey.

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2

Feltrin, Luca, Galini Tsoukaneri, Massimo Condoluci, Chiara Buratti, Toktam Mahmoodi, Mischa Dohler, and Roberto Verdone. "Narrowband IoT: A Survey on Downlink and Uplink Perspectives." IEEE Wireless Communications 26, no. 1 (February 2019): 78–86. http://dx.doi.org/10.1109/mwc.2019.1800020.

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3

Malse, Akhilesh J., and Reena Kulshreshtha. "A Survey on Narrowband filtering Design using Microstrip filters." International Journal of Engineering Trends and Technology 34, no. 7 (April 25, 2016): 327–30. http://dx.doi.org/10.14445/22315381/ijett-v34p265.

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4

Shara, M. M., M. Potter, A. F. J. Moffat, and L. F. Smith. "A Deep Survey for Faint Galactic Wolf-Rayet Stars." Symposium - International Astronomical Union 143 (1991): 591–94. http://dx.doi.org/10.1017/s0074180900045952.

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Surveys of the Galaxy for Wolf-Rayet (WR) stars are mostly based on objective prism searches, and are generally complete to only about 13th visual magnitude. We are using direct narrowband and broadband Schmidt plates to survey large areas of the southern Milky Way for WR stars to 17-18th magnitude. We expect to find more than 50 new WR stars. The newly detected stars should be among the most distant and/or reddened known in the Galaxy. The survey is also designed to test the completeness of previous bright WR star surveys, and thus to help settle debates over the Initial Mass Function of the most massive stars. We have now located 13 new WR stars in a 40 square degree region in Carina where 24 WR stars were already known. A 25% incompleteness in detection of WR stars as close as 2-3 kpc is suggested.

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5

Hickson, Paul, and Mark K. Mulrooney. "University of British Columbia–NASA Multi‐Narrowband Survey. I. Description and Photometric Properties of the Survey." Astrophysical Journal Supplement Series 115, no. 1 (March 1998): 35–42. http://dx.doi.org/10.1086/313080.

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6

Corradi, R. L. M., L. Magrini, N. A. Walton, A. A. Zijlstra, J. R. Walsh, M. Perinotto, D. L. Pollacco, D. J. Lennon, and R. Greimel. "First Results From the Local Group Census: Planetary Nebulae in Sextans B." Symposium - International Astronomical Union 209 (2003): 561. http://dx.doi.org/10.1017/s0074180900209704.

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The Local Group Census is a narrowband survey of all the galaxies of the Local Group (LG) with Dec ≥ −30°, being carried out as part of the Isaac Newton Group's Wide Field Survey programme. Observations are being obtained with the Wide Field Camera at the 2.5m Isaac Newton telescope, equipped with a mosaic of four 2k x 4k EEV CCDs covering a field of view of 34′ x 34′.

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7

Thompson, D., F. Mannucci, and S. V. W. Beckwith. "A Narrowband Imaging Survey for High Redshift Galaxies in the Near Infrared." Astronomical Journal 112 (November 1996): 1794. http://dx.doi.org/10.1086/118141.

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8

Ajiki, Masaru, Bahram Mobasher, Yoshiaki Taniguchi, Yasuhiro Shioya, Tohru Nagao, Takashi Murayama та Shunji S. Sasaki. "Narrowband Survey of the GOODS Fields: Search for Lyα Emitters atz= 5.7". Astrophysical Journal 638, № 2 (20 лютого 2006): 596–602. http://dx.doi.org/10.1086/499097.

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9

Bland-Hawthorn, Joss, and D. Heath Jones. "Taurus Tunable Filter: A Flexible Approach to Narrowband Imaging." Publications of the Astronomical Society of Australia 15, no. 1 (1998): 44–49. http://dx.doi.org/10.1071/as98044.

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AbstractThe Taurus Tunable Filter (TTF) is a tunable narrowband interference filter covering wavelengths from 6300 Å to the sensitivity drop-off of conventional CCDs (∼9600 Å), although a blue ‘arm’ (4000–6500 Å) is to be added by the end of 1997. The TTF offers monochromatic imaging at the Cassegrain foci of both the Anglo-Australian and William Herschel Telescopes, with an adjustable passband of between 6 and 60 Å. In addition, frequency switching with the TTF can be synchronised with movement of charge (charge shuffling) on the CCD, which has important applications to many astrophysical problems. Here we review the different modes of TTF and suggest their use for follow-up narrowband imaging to the AAO/UKST Galactic Plane Hα Survey.

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10

Gajjar, Vishal, Dominic LeDuc, Jiani Chen, Andrew P. V. Siemion, Sofia Z. Sheikh, Bryan Brzycki, Steve Croft, et al. "Searching for Broadband Pulsed Beacons from 1883 Stars Using Neural Networks." Astrophysical Journal 932, no. 2 (June 1, 2022): 81. http://dx.doi.org/10.3847/1538-4357/ac6dd5.

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Abstract The search for extraterrestrial intelligence at radio frequencies has largely been focused on continuous-wave narrowband signals. We demonstrate that broadband pulsed beacons are energetically efficient compared to narrowband beacons over longer operational timescales. Here, we report the first extensive survey searching for such broadband pulsed beacons toward 1883 stars as a part of the Breakthrough Listen’s search for advanced intelligent life. We conducted 233 hr of deep observations across 4–8 GHz using the Robert C. Byrd Green Bank Telescope and searched for three different classes of signals with artificial (or negative) dispersion. We report a detailed search—leveraging a convolutional neural network classifier on high-performance GPUs—deployed for the very first time in a large-scale search for signals from extraterrestrial intelligence. Due to the absence of any signal-of-interest from our survey, we place a constraint on the existence of broadband pulsed beacons in our solar neighborhood: ≲1 in 1000 stars have transmitter power densities ≳105 W Hz−1 repeating ≤500 s at these frequencies.

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11

Bassett, Christopher, Alex De Robertis, and Christopher D. Wilson. "Broadband echosounder measurements of the frequency response of fishes and euphausiids in the Gulf of Alaska." ICES Journal of Marine Science 75, no. 3 (November 13, 2017): 1131–42. http://dx.doi.org/10.1093/icesjms/fsx204.

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Abstract Broadband acoustic scattering techniques are not widely used in fisheries acoustics, but this may change due to the recent commercial availability of a broadband echosounder system operating at frequencies commonly used in fisheries surveys. A four-channel (15–150 kHz) broadband echosounder was used to investigate the potential of broadband methods to improve species discrimination during a walleye pollock (Gadus chalcogrammus) survey in the Gulf of Alaska. Narrowband echosounders combined with mid-water and bottom trawls were used to identify aggregations of interest for broadband measurements. Broadband frequency responses were measured for multiple pelagic and semi-demersal fishes as well as euphausiids. No clear patterns in the broadband frequency responses were identified that would aid in discrimination among the commonly encountered swimbladder-bearing species. The results are consistent with narrowband observations and suggest that both techniques face the same challenges when attempting to discriminate among acoustically similar species as frequency responses overlap within the measured bandwidth. However, examples are presented in which broadband frequency responses provide additional information about near-resonant scatterers. The benefits of broadband operations have not been fully realized and widespread adoption of broadband techniques and improved processing algorithms may yield improved acoustic-based species discrimination for use during fisheries surveys.

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12

Masheder, M. R. W., S. Phillipps та Q. A. Parker. "Scientific Background to the UKST Hα Survey". Publications of the Astronomical Society of Australia 15, № 1 (1998): 5–8. http://dx.doi.org/10.1071/as98005.

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AbstractThe dominant process in the evolution of spiral galaxies like our own is clearly the formation of new stars, and the leading optical indicator of this is Hα emission. Considering the tremendous importance of star formation and its variation within and between galaxies, it is surprising just how little survey work has been carried out at Hα. After the successful development of Tech Pan films for deep photographic imaging with the UKST, and given the particular sensitivity of Tech Pan at wavelengths near Hα, it was natural to consider the possibilities for a narrowband Hα imaging survey of large angular extent. This idea quickly developed into a full-blown survey of the whole of the Southern Milky Way, of the Magellanic Clouds, and of selected extragalactic regions of interest such as that around the Virgo Cluster. This special issue is devoted to the discussion of the details of making and using this survey.

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13

Galera-Rosillo, R., R. L. M. Corradi, and A. Mampaso. "A deep narrowband survey for planetary nebulae at the outskirts of M 33." Astronomy & Astrophysics 612 (April 2018): A35. http://dx.doi.org/10.1051/0004-6361/201731383.

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Context. Planetary nebulae (PNe) are excellent tracers of stellar populations with low surface brightness, and therefore provide a powerful method to detect and explore the rich system of substructures discovered around the main spiral galaxies of the local group. Aim. We searched the outskirts of the local group spiral galaxy M 33 (the Triangulum) for PNe to gain new insights into the extended stellar substructure on the northern side of the disc and to study the existence of a faint classical halo. Methods. The search is based on wide field imaging covering a 4.5 square degree area out to a maximum projected distance of about 40 kpc from the centre of the galaxy. The PN candidates are detected by the combination of images obtained in narrowband filters selecting the [OIII]λ5007 Å and Hα + [NII] nebular lines and in the continuum g′ and r′ broadband filters. Results. Inside the bright optical disc of M 33, eight new PN candidates were identified, three of which were spectroscopically confirmed. No PN candidates were found outside the limits of the disc. Fourteen additional sources showing [OIII] excess were also discovered. Conclusions. The absence of bright PN candidates in the area outside the galaxy disc covered by this survey sets an upper limit to the luminosity of the underlying population of ~1.6 × 107 L⊙, suggesting the lack of a massive classical halo, which is in agreement with the results obtained using the red giant branch population.

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14

Jones, D. Heath, and Joss Bland‐Hawthorn. "The Taurus Tunable Filter Field Galaxy Survey: Sample Selection and Narrowband Number Counts." Astrophysical Journal 550, no. 2 (April 2001): 593–611. http://dx.doi.org/10.1086/319793.

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15

Harish, Santosh, Isak G. B. Wold, Sangeeta Malhotra, James E. Rhoads, Weida Hu, Junxian Wang, Zhen-ya Zheng та ін. "New Spectroscopic Confirmations of Lyα Emitters at Z ∼ 7 from the LAGER Survey". Astrophysical Journal 934, № 2 (1 серпня 2022): 167. http://dx.doi.org/10.3847/1538-4357/ac7cf1.

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Abstract We report spectroscopic confirmations of 15 Lyα galaxies at z ∼ 7, implying a spectroscopic confirmation rate of ∼80% on candidates selected from the Lyα Galaxies in the Epoch of Reionization (LAGER), which is the largest (24 deg2) survey aimed at finding Lyα emitters (LAEs) at z ∼ 7 and uses deep narrowband imaging from the Dark Energy Camera at CTIO. LAEs at high redshifts are sensitive probes of cosmic reionization, and narrowband imaging is a robust and effective method for selecting a large number of LAEs. In this work, we present results from the spectroscopic follow-up of LAE candidates in two LAGER fields, COSMOS and WIDE-12, using observations from Keck/LRIS. We report the successful detection of Lyα emission in 15 candidates. Three of these in COSMOS have matching confirmations from a previous spectroscopic follow-up and are part of the overdense region, LAGER-z7OD1. Two other candidates that were not detected with LRIS have prior spectroscopic confirmations from Magellan. Including these, we obtain a spectroscopic confirmation success rate of ∼80% for LAGER LAE candidates. Thorough checks were performed to reject the possibility of these detections being foreground emission resulting with a probability of, at most, one contaminant. We do not detect any other UV nebular lines in our LRIS spectra, apart from Lyα. We estimate a 2σ upper limit for the ratio of N v/Lyα, f NV/f Lyα ≲ 0.27. Including confirmations from this work, a total of 33 LAE sources from LAGER are now spectroscopically confirmed. LAGER has more than doubled the sample of spectroscopically confirmed LAE sources at z ∼ 7.

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16

Khader, Ammar Abdul-Hamed, and Zozan Azeez Ayoub. "The Cognitive Radio and Internet of Things." European Journal of Engineering Research and Science 5, no. 8 (August 24, 2020): 899–903. http://dx.doi.org/10.24018/ejers.2020.5.8.2012.

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Cognitive Radio (CR) and Internet of Things (IoT) is an effective step into the smart technology world. Several frameworks are proposed to build CR and IoT. The phases of the interconnection between IoT and CR is; spectrum sensing, spectrum sharing, and spectrum management. This paper presents a survey of CR based IoT and mentions some previous works. It highlights with details the spectrum sensing stage for both narrowband and wideband.

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Khader, Ammar Abdul-Hamed, and Zozan Azeez Ayoub. "Cognitive Radio and Internet of Things." European Journal of Engineering and Technology Research 5, no. 8 (August 24, 2020): 899–903. http://dx.doi.org/10.24018/ejeng.2020.5.8.2012.

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Cognitive Radio (CR) and Internet of Things (IoT) is an effective step into the smart technology world. Several frameworks are proposed to build CR and IoT. The phases of the interconnection between IoT and CR is; spectrum sensing, spectrum sharing, and spectrum management. This paper presents a survey of CR based IoT and mentions some previous works. It highlights with details the spectrum sensing stage for both narrowband and wideband.

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18

Dennison, B., J. H. Simonetti, G. A. Topasna, and C. Kelleher. "An Imaging Survey of the Galactic H-Alpha Emission with Arcminute Resolution." Symposium - International Astronomical Union 179 (1998): 182–83. http://dx.doi.org/10.1017/s0074180900128530.

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We are presently carrying out a northern hemisphere survey of the Galactic Hα emission. Our instrument, the Virginia Tech Spectral Line Imaging Camera (SLIC) utilizes a fast objective lens (f/1.2) with a cryogenically-cooled TK 512×512 CCD. A filter wheel in front of the lens allows us to select interference filters, including a narrowband Hα filter and a broader bandpass continuum filter in a line free part of the spectrum. The fast optics in combination with the low noise CCD result in sub-Rayleigh sensitivity at confusion limited levels. (1 Rayleigh = 106/4π photons cm–2 s–1 sr–1.) This corresponds to an emission measure sensitivity of ≈ 1 pc cm–6. Parameters of our system are given in Table 1.

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19

Cook, David O., Mansi M. Kasliwal, Angela Van Sistine, David L. Kaplan, Jessica S. Sutter, Thomas Kupfer, David L. Shupe, et al. "Census of the Local Universe (CLU) Narrowband Survey. I. Galaxy Catalogs from Preliminary Fields." Astrophysical Journal 880, no. 1 (July 17, 2019): 7. http://dx.doi.org/10.3847/1538-4357/ab2131.

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20

Popli, Sakshi, Rakesh Kumar Jha, and Sanjeev Jain. "A Survey on Energy Efficient Narrowband Internet of Things (NBIoT): Architecture, Application and Challenges." IEEE Access 7 (2019): 16739–76. http://dx.doi.org/10.1109/access.2018.2881533.

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21

Laursen, Peter, Jesper Sommer-Larsen, Bo Milvang-Jensen, Johan P. U. Fynbo та Alexei O. Razoumov. "Lyman α-emitting galaxies in the epoch of reionization". Astronomy & Astrophysics 627 (липень 2019): A84. http://dx.doi.org/10.1051/0004-6361/201833645.

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With a total integration time of 168 h and a narrowband filter tuned to Lyα emission from z = 8.8, the UltraVISTA survey has set out to find some of the most distant galaxies, on the verge of the epoch of reionization. Previous calculations of the expected number of detected Lyα-emitting galaxies (LAEs) at this redshift based for example on extrapolation of lower-redshift luminosity functions did not explicitly take into account the radiative transfer of Lyα. In this work we have combined a theoretical model for the halo mass function, that is, the expected number of haloes per volume, with numerical results from high-resolution cosmological hydro-simulations post-processed with radiative transfer of ionizing UV and Lyα radiation, assessing the visibility of LAEs residing in these haloes. We have taken into account uncertainties such as cosmic variance and the anisotropic escape of Lyα, and predict that once the survey has finished, the probabilities of detecting none, one, or more than one are roughly 90%, 10%, and 1%, respectively. This is a significantly smaller success rate than in earlier predictions, due to the combined effect of a highly neutral intergalactic medium (IGM) scattering Lyα to such large distances from the galaxy that they fall outside the observational aperture, and to the actual depth of the survey being less than predicted. Because the IGM affects narrowband (NB) and broadband (BB) magnitudes differently, we argue for a relaxed colour selection criterion of mNB − mBB ≃ +0.85 in the AB system. Since the flux is dominated by the continuum, however, even if a galaxy is detectable in the NB, its probability of being selected as a narrowband excess object is ≲35%. Various additional properties of galaxies at this redshift are predicted, for example, the Lyα and UV luminosity functions, the stellar mass–halo mass relation, the spectral shape, the optimal aperture, as well as the anisotropic escape of Lyα through both the dusty, interstellar medium and through the partly neutral IGM. Finally, we describe and make public a fast numerical code for adding numbers with asymmetric uncertainties (“x+σ+−σ−”) which proves significantly more precise than the standard, but wrong, way of separately adding upper and lower uncertainties in quadrature.

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22

Perez, Lucia A., Sangeeta Malhotra, James E. Rhoads, Peter Laursen та Isak G. B. Wold. "Probing Patchy Reionization with the Void Probability Function of Lyα Emitters". Astrophysical Journal 940, № 2 (24 листопада 2022): 102. http://dx.doi.org/10.3847/1538-4357/ac9b57.

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Abstract We probe what constraints for the global ionized hydrogen fraction the void probability function (VPF) clustering can give for the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) narrowband survey as a function of area. Neutral hydrogen acts like a fog for Lyα emission, and measuring the drop in the luminosity function of Lyα emitters (LAEs) has been used to constrain the ionization fraction in narrowband surveys. However, the clustering of LAEs is independent of the luminosity function’s inherent evolution, and can offer additional constraints for reionization under different models. The VPF measures how likely a given circle is to be empty. It is a volume-averaged clustering statistic that traces the behavior of higher-order correlations, and its simplicity offers helpful frameworks for planning surveys. Using the Jensen et al. simulations of LAEs within various amounts of ionized intergalactic medium, we predict the behavior of the VPF in one (301 × 150.5 × 30 Mpc3), four (5.44 × 106 Mpc3), or eight (1.1 × 107 Mpc3) fields of LAGER imaging. We examine the VPF at 5′ and 13′, corresponding to the minimum scale implied by the LAE density and the separation of the 2D VPF from random, and the maximum scale from the eight-field 15.5 deg2 LAGER area. We find that even a single DECam field of LAGER (2–3 deg2) could discriminate between mostly neutral versus ionized. Additionally, we find four fields allow for the distinction between 30%, 50%, and 95% ionized, and eight fields could even distinguish between 30%, 50%, 73%, and 95% ionized.

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23

Zhu, Xing Le, Chang Han Xiao, and Zhen Ning Yao. "Effect of Ship's Motion on Wave-Generated Magnetic Field in Marine Magnetic Survey." Applied Mechanics and Materials 380-384 (August 2013): 228–31. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.228.

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The survey ship would be interfered by wave-generated magnetic field in marine survey. The waves magnetic field is difficult to eliminate because it is the signal in low frequency like ships magnetization field. When survey ship sails, the frequency of waves magnetic field would change. It was found that the frequency has a linear relationship with ships speed and varies in sine or cosine with the angle between ships and waves directions. Ocean waves PSD would be compressed and strong noise of low frequency in narrowband turns up when ship sails in the same direction of waves. The frequency band of PSD would be broadened and small interference occurs while ships direction is opposite. A conclusion can be drawn that survey ship should sail reversely with ocean waves in marine magnetic survey, so the magnetic field induced by ocean waves would extend to high frequency and it is better for noise elimination.

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24

Nakajima, Kimihiko, Masami Ouchi, Kazuhiro Shimasaku, Yoshiaki Ono, Janice C. Lee, Sebastien Foucaud, Chun Ly та ін. "AVERAGE METALLICITY AND STAR FORMATION RATE OF Lyα EMITTERS PROBED BY A TRIPLE NARROWBAND SURVEY". Astrophysical Journal 745, № 1 (27 грудня 2011): 12. http://dx.doi.org/10.1088/0004-637x/745/1/12.

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25

Giménez-Arteaga, Clara, Gabriel B. Brammer, Danilo Marchesini, Luis Colina, Varun Bajaj, Malte Brinch, Daniela Calzetti та ін. "High-resolution Hubble Space Telescope Imaging Survey of Local Star-forming Galaxies. I. Spatially Resolved Obscured Star Formation with Hα and Paschen-β Recombination Lines". Astrophysical Journal Supplement Series 263, № 1 (1 листопада 2022): 17. http://dx.doi.org/10.3847/1538-4365/ac958c.

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Abstract We present a sample of 24 local star-forming galaxies observed with broadband and narrowband photometry from the Hubble Space Telescope (HST) that are part of the Great Observatories All-sky Luminous Infrared Galaxies Survey of local luminous and ultraluminous infrared galaxies. With narrowband filters around the emission lines Hα (and [N ii]) and Paβ, we obtain robust estimates of the dust attenuation affecting the gas in each galaxy, probing higher attenuation than can be traced by the optical Balmer decrement Hα/Hβ alone by a factor of >1 mag. We also infer the dust attenuation toward the stars via a spatially resolved spectral energy distribution fitting procedure that uses all available HST imaging filters. We use various indicators to obtain the star formation rate (SFR) per spatial bin and find that Paβ traces star-forming regions where the Hα and the optical stellar continuum are heavily obscured. The dust-corrected Paβ SFR recovers the 24 μm inferred SFR with a ratio of −0.14 ± 0.32 dex and the SFR inferred from the 8 to 1000 μm infrared luminosity at −0.04 ± 0.23 dex. Both in a spatially resolved and integrated sense, rest-frame near-infrared recombination lines can paint a more comprehensive picture of star formation across cosmic time, particularly with upcoming JWST observations of Paschen-series line emission in galaxies as early as the epoch of reionization.

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26

Dennison, Brian, John H. Simonetti та Gregory A. Topasna. "An Imaging Survey of Northern Galactic Hα Emission with Arcminute Resolution". Publications of the Astronomical Society of Australia 15, № 1 (1998): 147–48. http://dx.doi.org/10.1071/as98147.

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AbstractWe present preliminary results from a high-resolution, high-sensitivity imaging survey of the northern galactic Hα emission. The survey is carried out using the Spectral Line Imaging Camera (SLIC) which incorporates a fast (f/1·2) lens attached to a cryogenic CCD in combination with a narrowband interference filter. The pixel size is 1·6 arcminutes and the diameter of each field is 10°. The fast optics, narrow bandpass (1·7 nm) filter, and high quantum-efficiency, low-noise CCD yield a high brightness sensitivity to Hα emission on arcminute scales. This gives an equivalent sensitivity to emission measure structure below 1 pc cm−6. Some faint features detected include a supershell connected with the star forming region W4 extending 7° above the galactic plane, and filaments possibly related to galactic loops II and III. In addition, we have carried out deep observations of fields in which anisotropies in the cosmic microwave background radiation have been detected. Our observations place stringent limits upon the contribution to the apparent microwave fluctuations from free–free emission in the galactic foreground.

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27

Magakian, Tigran Yu, Elena H. Nikogossian, Colin Aspin, Tae-Soo Pyo, Tigran Khanzadyan, Tigran Movsessian, Michael D. Smith, et al. "A WIDE-FIELD NARROWBAND OPTICAL SURVEY OF THE BRAID NEBULA STAR FORMATION REGION IN CYGNUS OB7." Astronomical Journal 139, no. 3 (February 2, 2010): 969–83. http://dx.doi.org/10.1088/0004-6256/139/3/969.

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28

Козырева, Ольга, Olga Kozyreva, Вячеслав Пилипенко, Vyacheslav Pilipenko, Марк Энгебретсон, Mark Engebretson, Дмитрий Климушкин, Dmitriy Klimushkin, Павел Магер, and Pavel Mager. "Correspondence between the ULF wave power spatial distribution and auroral oval boundaries." Solar-Terrestrial Physics 2, no. 2 (August 10, 2016): 46–65. http://dx.doi.org/10.12737/20999.

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The world-wide spatial distribution of the wave power in the Pc5 band during magnetic storms has been compared with auroral oval boundaries. The poleward and equatorward auroral oval boundaries are estimated using either the British Antarctic Survey database containing IMAGE satellite UV observations of the aurora or the OVATION model based on the DMSP particle data. The “epicenter” of the spectral power of broadband Pc5 fluctuations during the storm growth phase is mapped inside the auroral oval. During the storm recovery phase, the spectral power of narrowband Pc5 waves, both in the dawn and dusk sectors, is mapped inside the auroral oval or around its equatorward boundary. This observational result confirms previously reported effects: the spatial/temporal variations of the Pc5 wave power in the morning/pre-noon sector are closely related to the dynamics of the auroral electrojet and magnetospheric field-aligned currents. At the same time, narrowband Pc5 waves demonstrate typical resonant features in the amplitude-phase latitudinal structure. Thus, the location of the auroral oval or its equatorward boundary is the preferred latitude for magnetospheric field-line Alfven resonator excitation. This effect is not taken into account by modern theories of ULF Pc5 waves, but it could be significant for the development of more adequate models.

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Höyhtyä, Marko, and Jussi Martio. "Integrated Satellite–Terrestrial Connectivity for Autonomous Ships: Survey and Future Research Directions." Remote Sensing 12, no. 15 (August 4, 2020): 2507. http://dx.doi.org/10.3390/rs12152507.

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An autonomous vessel uses multiple different radio technologies such as satellites, mobile networks and dedicated narrowband systems, to connect to other ships, services, and the remote operations center (ROC). In-ship communication is mainly implemented with wired technologies but also wireless links can be used. In this survey paper, we provide a short overview of autonomous and remote-controlled systems. This paper reviews 5G-related standardization in the maritime domain, covering main use cases and both the role of autonomous ships and that of people onboard. We discuss the concept of a connectivity manager, an intelligent entity that manages complex set of technologies, integrating satellite and terrestrial technologies together, ensuring robust in-ship connections and ship-to-outside connections in any environment. This survey paper describes the architecture and functionalities of connectivity management required for an autonomous ship to be able to operate globally. As a specific case example, we have implemented a research environment consisting of ship simulators with connectivity components. Our simulation results on the effects of delays to collision avoidance confirm the role of reliable connectivity for safety. Finally, we outline future research directions for autonomous ship connectivity research, providing ideas for further work.

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Sing, D. K., J. M. Désert, J. J. Fortney, A. Lecavelier des Etangs, G. E. Ballester, J. Cepa, D. Ehrenreich, et al. "Gran Telescopio Canarias OSIRIS transiting exoplanet atmospheric survey: detection of potassium in XO-2b from narrowband spectrophotometry." Astronomy & Astrophysics 527 (January 27, 2011): A73. http://dx.doi.org/10.1051/0004-6361/201015579.

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López, Rosario, Angels Riera, Robert Estalella, and Gabriel Gómez. "A survey of IRAS young stellar object candidates." Astronomy & Astrophysics 648 (April 2021): A57. http://dx.doi.org/10.1051/0004-6361/202037752.

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Context. Jets and outflows are associated with young stellar objects across the stellar mass spectrum, from brown dwarf protostars to massive Ae/Be stars. Frequently the jet morphology is spatially discontinuous because of the temporal variability of the ejection from the driving source. Images covering a wide field of view around the jet-driving source are useful to map the large-scale jet emission and to explore the mass ejection history. Aims. The aim of our work was to search for large-scale optical Herbig-Haro (HH) objects lying in a wide field around a sample of IRAS sources, which are candidates to trace young stellar objects. Methods. Deep narrowband images through the Hα and [S II] emission lines, and through an off-line continuum filter, covering a wide (~15′) field around the IRAS targets were acquired. The images in the three filters were analyzed to identify shock-excited line emission (i.e., HH) in contrast to scattered line emission. Results. New images of a sample of 15 IRAS sources, obtained in a homogeneous way are presented. HH emission was detected in six fields, and the astrometry of the knot features is given. The nature of the extended emission as scattered emission around nine of the IRAS targets is confirmed. For seven IRAS sources with unclear optical counterparts, a more plausible counterpart is proposed. A refined value of the source distance is reported for seven targets. An update of the main data available for each of the sampled fields, including images from public data archives, is also presented.

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Arjoune, Youness, and Naima Kaabouch. "A Comprehensive Survey on Spectrum Sensing in Cognitive Radio Networks: Recent Advances, New Challenges, and Future Research Directions." Sensors 19, no. 1 (January 2, 2019): 126. http://dx.doi.org/10.3390/s19010126.

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Cognitive radio technology has the potential to address the shortage of available radio spectrum by enabling dynamic spectrum access. Since its introduction, researchers have been working on enabling this innovative technology in managing the radio spectrum. As a result, this research field has been progressing at a rapid pace and significant advances have been made. To help researchers stay abreast of these advances, surveys and tutorial papers are strongly needed. Therefore, in this paper, we aimed to provide an in-depth survey on the most recent advances in spectrum sensing, covering its development from its inception to its current state and beyond. In addition, we highlight the efficiency and limitations of both narrowband and wideband spectrum sensing techniques as well as the challenges involved in their implementation. TV white spaces are also discussed in this paper as the first real application of cognitive radio. Last but by no means least, we discuss future research directions. This survey paper was designed in a way to help new researchers in the field to become familiar with the concepts of spectrum sensing, compressive sensing, and machine learning, all of which are the enabling technologies of the future networks, yet to help researchers further improve the efficiently of spectrum sensing.

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Huang, Yuping, Marin M. Anderson, Gregg Hallinan, T. Joseph W. Lazio, Danny C. Price, and Yashvi Sharma. "A Matched Survey for the Enigmatic Low Radio Frequency Transient ILT J225347+862146." Astrophysical Journal 925, no. 2 (February 1, 2022): 171. http://dx.doi.org/10.3847/1538-4357/ac4048.

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Abstract Discovered in 2011 with LOFAR, the 15 Jy low-frequency radio transient ILT J225347+862146 heralds a potentially prolific population of radio transients at <100 MHz. However, subsequent transient searches in similar parameter space yielded no detections. We test the hypothesis that these surveys at comparable sensitivity have missed the population due to mismatched survey parameters. In particular, the LOFAR survey used only 195 kHz of bandwidth at 60 MHz, while other surveys were at higher frequencies or had wider bandwidth. Using 137 hr of all-sky images from the Owens Valley Radio Observatory Long Wavelength Array, we conduct a narrowband transient search at ∼10 Jy sensitivity with timescales from 10 minutes to 1 day and a bandwidth of 722 kHz at 60 MHz. To model the remaining survey selection effects, we introduce a flexible Bayesian approach for inferring transient rates. We do not detect any transient and find compelling evidence that our nondetection is inconsistent with the detection of ILT J225347+862146. Under the assumption that the transient is astrophysical, we propose two hypotheses that may explain our nondetection. First, the transient population associated with ILT J225347+862146 may have a low all-sky density and display strong temporal clustering. Second, ILT J225347+862146 may be an extreme instance of the fluence distribution, of which we revise the surface density estimate at 15 Jy to 1.1 × 10−7 deg−2 with a 95% credible interval of (3.5 × 10−12, 3.4 × 10−7) deg−2. Finally, we find a previously identified object coincident with ILT J225347+862146 to be an M dwarf at 420 pc.

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Mwakwata, Collins Burton, Hassan Malik, Muhammad Mahtab Alam, Yannick Le Moullec, Sven Parand, and Shahid Mumtaz. "Narrowband Internet of Things (NB-IoT): From Physical (PHY) and Media Access Control (MAC) Layers Perspectives." Sensors 19, no. 11 (June 8, 2019): 2613. http://dx.doi.org/10.3390/s19112613.

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Narrowband internet of things (NB-IoT) is a recent cellular radio access technology based on Long-Term Evolution (LTE) introduced by Third-Generation Partnership Project (3GPP) for Low-Power Wide-Area Networks (LPWAN). The main aim of NB-IoT is to support massive machine-type communication (mMTC) and enable low-power, low-cost, and low-data-rate communication. NB-IoT is based on LTE design with some changes to meet the mMTC requirements. For example, in the physical (PHY) layer only single-antenna and low-order modulations are supported, and in the Medium Access Control (MAC) layers only one physical resource block is allocated for resource scheduling. The aim of this survey is to provide a comprehensive overview of the design changes brought in the NB-IoT standardization along with the detailed research developments from the perspectives of Physical and MAC layers. The survey also includes an overview of Evolved Packet Core (EPC) changes to support the Service Capability Exposure Function (SCEF) to manage both IP and non-IP data packets through Control Plane (CP) and User Plane (UP), the possible deployment scenarios of NB-IoT in future Heterogeneous Wireless Networks (HetNet). Finally, existing and emerging research challenges in this direction are presented to motivate future research activities.

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Lalchand, Bhavana, Wen-Ping Chen, Beth A. Biller, Loïc Albert, Katelyn Allers, Sophie Dubber, Zhoujian Zhang, et al. "A Novel Survey for Young Substellar Objects with the W-band Filter. V. IC 348 and Barnard 5 in the Perseus Cloud." Astronomical Journal 164, no. 4 (September 6, 2022): 125. http://dx.doi.org/10.3847/1538-3881/ac8547.

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Abstract We report the discovery of substellar objects in the young star cluster IC 348 and the neighboring Barnard 5 dark cloud, both at the eastern end of the Perseus star-forming complex. The substellar candidates are selected using narrowband imaging, i.e., on and off photometric technique with a filter centered around the water absorption feature at 1.45 μm, a technique proven to be efficient in detecting water-bearing substellar objects. Our spectroscopic observations confirm three brown dwarfs in IC 348. In addition, the source WBIS 03492858+3258064, reported in this work, is the first confirmed brown dwarf discovered toward Barnard 5. Together with the young stellar population selected via near- and mid-infrared colors using the Two Micron All Sky Survey and the Wide-field Infrared Survey Explorer, we diagnose the relation between stellar versus substellar objects with the associated molecular clouds. Analyzed by Gaia EDR3 parallaxes and kinematics of the cloud members across the Perseus region, we propose the star formation scenario of the complex under influence of the nearby OB association.

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Franz, Noah, Steve Croft, Andrew P. V. Siemion, Raffy Traas, Bryan Brzycki, Vishal Gajjar, Howard Isaacson, et al. "The Breakthrough Listen Search for Intelligent Life: Technosignature Search of Transiting TESS Targets of Interest." Astronomical Journal 163, no. 3 (February 1, 2022): 104. http://dx.doi.org/10.3847/1538-3881/ac46c9.

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Abstract The Breakthrough Listen (BL) Initiative, as part of its larger mission, is performing the most thorough technosignature search of nearby stars. Additionally, BL is collaborating with scientists working on NASA’s Transiting Exoplanet Survey Satellite (TESS) to examine TESS Targets of Interest (TOIs) for technosignatures. Here, we present a 1–11 GHz radio technosignature search of 61 TESS TOIs that were in transit during their BL observation at the Robert C. Byrd Green Bank Telescope. We performed a narrowband Doppler drift search with a minimum S/N threshold of 10 across a drift rate range of ±4 Hz s−1 with a resolution of 3 Hz. We removed radio frequency interference by comparing signals across cadences of target sources. After interference removal, there are no remaining events in our survey, and therefore no technosignature signals of interest detected in this work. This null result implies that at L, S, C, and X bands, fewer than 52%, 20%, 16%, and 15%, respectively, of TESS TOIs possess a transmitter with an equivalent isotropic radiated power greater than a few times 1014 W.

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Zheng, Zhen-Ya, James E. Rhoads, Jun-Xian Wang, Sangeeta Malhotra, Alistair Walker, Thomas Mooney, Chunyan Jiang, et al. "Design for the First Narrowband Filter for the Dark Energy Camera: Optimizing the LAGER Survey for z ∼ 7 Galaxies." Publications of the Astronomical Society of the Pacific 131, no. 1001 (June 3, 2019): 074502. http://dx.doi.org/10.1088/1538-3873/ab1c32.

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38

Sinko, Anton, Ilya Ozheredov, Elena Rudneva, Vera Manomenova, Natalia Kozlova, Natalia Lobova, Alexey Voloshin, Jean-Louis Coutaz, and Alexander Shkurinov. "Perspective on Terahertz Applications of Molecular Crystals." Electronics 11, no. 17 (August 30, 2022): 2731. http://dx.doi.org/10.3390/electronics11172731.

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In this review, we present a survey on the use of molecular nonlinear crystals in the context of terahertz (THz) photonics. The fundamentals of nonlinear optics for converting optical and infrared radiation into THz radiation with the basic theory of femtosecond optical rectification and difference frequency generation are described. Various types of phase-matching conditions that can be achieved in molecular crystals are discussed. It is shown that one of the unique features of molecular crystals is the ability to generate tunable narrowband terahertz radiation using femtosecond lasers. We also provide a detailed description of the most commonly used and promising molecular crystals such as DAST, DSTMS, OH1, HMQ-TMS, DCMBI, and GUHP. This review also presents a description of recent publications which show the prospects of using molecular nonlinear optical crystals in THz photonics.

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Arrigoni Battaia, Fabrizio, Y. Yang, J. F. Hennawi, Y. Matsuda, T. Yamada та T. Hayashino. "A Deep Narrow Band Imaging Search for CIVλ1548Å and HeIIλ1640Å Emission from Lyman Alpha Blobs". Proceedings of the International Astronomical Union 9, S304 (жовтень 2013): 32–33. http://dx.doi.org/10.1017/s1743921314003214.

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AbstractTo study the nature of Lyα blobs (aka LABs), we conduct a deep C IV and He II narrowband imaging survey of 13 Lyα blobs located in SSA22 proto-cluster at z ~ 3.1. We reach the unprecedented sensitivity, 5σ surface brightness limit of 2.1 − 3.4 × 10−18 erg s−1 cm−2 arcsec−2 per 1 arcsec2 aperture for two emission lines. We do not detect any extended C IV and He II emission, placing strong upper limits on the He II/Lyα and C IV/Lyα line ratios. We compare our limits with data in the literature related to the nebulae associated with high-redshift radio galaxies (HzRGs) and quasars, and we recover the data by modeling the LABs as nebulosities powered by a central QSO. For further information see Arrigoni Battaia et al. (2014).

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Tarter, Jill. "As Bad as Things are for Radio Astronomy in the Protected Bands -- They are Worse for SETI!" International Astronomical Union Colloquium 112 (1991): 273–87. http://dx.doi.org/10.1017/s0252921100004103.

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ABSTRACTIf the funding that has been requested in NASA’s FY89 budget is forthcoming, the Search for Extraterrestrial Intelligence (SETI) will inaugurate its microwave search program on Columbus Day, 1992. This systematic search for evidence of narrowband microwave signals generated by another technology will continue at several sites around the world until at least 1998. The search will be conducted in two modes: a sensitive targeted search of selected solar type stars covering 1 to 3 GHz, and an all sky survey that covers 1 to 10 GHz. This region of the spectrum is the quietest in terms of natural background noise from astrophysical sources and/or the terrestrial atmosphere, which is why it was chosen. Unfortunately, at the same time that terrestrial technology has enabled this systematic search, it also threatens to render the search all but impossible from the surface of the Earth. Terrestrial transmissions generated for an enormous number of different purposes will be the signals most frequently detected by the SETI systems! This paper describes the design decisions and observing plans that the SETI Program is now making in order to have a chance of successfully “listening” throujgh this heavily utilized portion of the spectrum. We do not yet know precisely how heroic our efforts to discriminate against and identify RFI may have to be, but we have been accumulating observational experience and data that demonstrate convincingly that the situation is rapidly growing worse. Because of the real-time nature of the signal processing being planned, SETI systems will provide an excellent opportunity to monitor, and perhaps identify, sources of narrowband interference within the radio astronomy bands at each site where observations are being conducted.

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Lin, Xiaojing, Zheng Zheng та Zheng Cai. "Probing the Diffuse Lyα Emission on Cosmological Scales: Lyα Emission Intensity Mapping Using the Complete SDSS-IV eBOSS". Astrophysical Journal Supplement Series 262, № 2 (20 вересня 2022): 38. http://dx.doi.org/10.3847/1538-4365/ac82e8.

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Abstract Based on Sloan Digital Sky Survey Data Release 16, we have detected the large-scale structure of Lyα emission in the universe at redshifts z = 2–3.5 by cross-correlating quasar positions and Lyα emission imprinted in the residual spectra of luminous red galaxies. We apply an analytical model to fit the corresponding Lyα surface brightness profile and multipoles of the redshift-space quasar–Lyα emission cross-correlation function. The model suggests an average cosmic Lyα luminosity density of 6.6 − 3.1 + 3.3 × 10 40 erg s − 1 cMpc − 3 , a ∼2σ detection with a median value about 8–9 times those estimated from deep narrowband surveys of Lyα emitters at similar redshifts. Although the low signal-to-noise ratio prevents us from a significant detection of the Lyα forest–Lyα emission cross-correlation, the measurement is consistent with the prediction of our best-fit model from quasar–Lyα emission cross-correlation within current uncertainties. We rule out the scenario where the Lyα photons mainly originate from quasars. We find that Lyα emission from star-forming galaxies, including contributions from that concentrated around the galaxy centers and that in diffuse Lyα-emitting halos, is able to explain the bulk of the Lyα luminosity density inferred from our measurements. Ongoing and future surveys can further improve the measurements and advance our understanding of the cosmic Lyα emission field.

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Šurjanac, Nenad, Marija Milosavljević, Mara Tabaković-Tošić, and Miroslava Marković. "Application of multispectral sensors and unmanned aerial system in Stara Planina region." Sustainable Forestry: Collection, no. 81-82 (2020): 175–86. http://dx.doi.org/10.5937/sustfor2081175q.

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In the area of Stara Planina mountain, a multispectral survey of forest vegetation was performed. Data acquisition was done with unmanned aerial system DJI Phantom 4 Pro, equipped with integrated RGB 20Mpix sensor, and MicaSense RedEdge M, 5-channel narrowband multispectral sensor. Data was collected in the form of images, and 4 composite orthomosaics were produced-broadband visible RGB, narrowband visible RGB, and with vegetation indices applied NDVI and NDRE. RGB orthomosaic showed no significant changes in canopies apart from the variability of levels of green. Orthomosaics with vegetation indices applied showed changes in the level of physiological activities of leaves. NDVI map showed the negative changes of the top of the canopies, while NDRE map showed more dramatic changes within the canopy as well. Besides the map, 5 polygons with different NDRE values were selected and their respective spectral signature graphs were produced. The areas with the lowest NDRE values had the highest reflectance values in all wavelengths, while the absorption of light is much higher in physiologically active vegetation. Values of NDRE lower than 0.479 were inspected from the ground. This kind of ground-truth provided evidence that the areas coded in red were with lower physiological activity due to the infestation by beech leaf-mining weevil Orchestes fagi L. Another interesting finding was that both NDVI and NDRE values were higher in the areas not directly exposed to the sunlight. The areas shaded by surrounding canopies received only diffuse light but it showed a more positive ratio between absorbed and reflected wavelength which could be characteristic of the Fagus Sylvatica species. The findings in this study showed a strong correlation between low values NDRE vegetation index and negative changes deep within the canopy of high vegetation, which can serve as an indicator of pest infestation in forestry.

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Seo, Byoung-Joon, Brian Gordon, Brian Kern, Andy Kuhnert, Dwight Moody, Richard Muller, Ilya Poberezhskiy, John Trauger, and Daniel Wilson. "Hybrid Lyot coronagraph for wide-field infrared survey telescope-astrophysics focused telescope assets: occulter fabrication and high contrast narrowband testbed demonstration." Journal of Astronomical Telescopes, Instruments, and Systems 2, no. 1 (March 8, 2016): 011019. http://dx.doi.org/10.1117/1.jatis.2.1.011019.

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Harikane, Yuichi. "Census of Lyα, [OIII]5007, Hα, and [CII]158μm Line Emission with ~1000 Low-mass Lyman Alpha Emitters at z = 4.9 – 7.0 Revealed with Subaru/Hyper-Suprime Cam Survey". Proceedings of the International Astronomical Union 14, S344 (серпень 2018): 449–52. http://dx.doi.org/10.1017/s1743921318006919.

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AbstractWe investigate Lyα, [Oiii] λ5007, Hα, and [Cii]158µm emission from 1,124 low-mass galaxies (typically M* ~ 108 Mʘ) at z = 4.9 - 7.0, composed of 1,092 Lyα emitters (LAEs) at z = 4.9 - 7.0 identified by Subaru/Hyper Suprime-Cam (HSC) narrowband surveys and 34 galaxies at z = 5.148 - 7.508 with deep ALMA [Cii]158µm data in the literature. At z = 4.9, we find that the rest-frame Hα equivalent width positively correlates with the rest-frame Lyα equivalent width EW0Lyα. At z = 5.7 - 7.0, there exists an interesting turn-over trend that the [ Oiii]/ Hα flux ratio increases in EW0Lyα ≃ 0 - 30 Å, and then decreases out to EW0Lyα ≃ 130 Å. We also identify an anti-correlation between a [ Cii] luminosity to star-formation rate ratio (L[CII]/SFR) and EW0Lyα at the >99% confidence level. We carefully investigate physical origins of the correlations, and find that a simple anti-correlation between EW0Lyα and metallicity explains self-consistently all of the relations identified in our study.

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McCarron, Adam P., Steven L. Finkelstein, Oscar A. Chavez Ortiz, Dustin Davis, Erin Mentuch Cooper, Intae Jung, Delaney R. White та ін. "Stellar Populations of Lyα-emitting Galaxies in the HETDEX Survey. I. An Analysis of LAEs in the GOODS-N Field". Astrophysical Journal 936, № 2 (1 вересня 2022): 131. http://dx.doi.org/10.3847/1538-4357/ac8546.

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Abstract We present the results of a stellar population analysis of 72 Lyα-emitting galaxies (LAEs) in GOODS-N at 1.9 < z < 3.5 spectroscopically identified by the Hobby−Eberly Telescope Dark Energy Experiment (HETDEX). We provide a method for connecting emission-line detections from the blind spectroscopic survey to imaging counterparts, a crucial tool needed as HETDEX builds a massive database of ∼1 million Lyα detections. Using photometric data spanning as many as 11 filters covering 0.4 < λ (μm) < 4.5 from the Hubble Space Telescope and Spitzer Space Telescope, we study the objects’ global properties and explore which properties impact the strength of Lyα emission. We measure a median stellar mass of 0.8 − 0.5 + 2.9 × 10 9 M ⊙ and conclude that the physical properties of HETDEX spectroscopically selected LAEs are comparable to LAEs selected by previous deep narrowband studies. We find that stellar mass and star formation rate correlate strongly with the Lyα equivalent width. We then use a known sample of z > 7 LAEs to perform a protostudy of predicting Lyα emission from galaxies in the epoch of reionization, finding agreement at the 1σ level between prediction and observation for the majority of strong emitters.

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Wang, Wei-Hao, Sebastien Foucaud, Bau-Ching Hsieh, Hung-Yu Jian, Lihwai Lin, Yen-Ting Lin, Jean Coupon, et al. "MUSUBI (MegaCam Ultra-deep Survey: u*-band Imaging) Data for the COSMOS and SXDS Fields." Astrophysical Journal Supplement Series 260, no. 2 (June 1, 2022): 54. http://dx.doi.org/10.3847/1538-4365/ac729e.

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Abstract The Subaru Hyper Suprime-Cam (HSC) Strategic Survey is the latest-generation multiband optical imaging survey for galaxy evolution and structure formation. The “Ultra-deep” component of the HSC survey provides grizy broadband images over ∼3.4 deg2 to detection limits of ∼26–28 AB, along with narrowband images, in the COSMOS and SXDS fields. These images provide an unprecedented combination of depths and area coverage, for studies of galaxies up to z ∼ 7. However, the lack of coverage at <4000 Å implies an incomplete sampling of the rest-frame UV at z ≲ 3, which is critically needed for understanding the buildup of stellar mass in later cosmic time. We conducted a multiyear CFHT u*-band imaging campaign in the two HSC Ultra-deep fields with CFHT MegaCam. By including shallower archival data, we reached 5σ depths of u* = 28.1 and 28.4 (AB) at the centers of the COSMOS and SXDS fields, respectively, and u* = 27.7 and 27.8 in the central 1 deg2 fields. The image quality is ≳ 0.″90, fairly good for the u* band. Both the photometric and astrometric quality of our data are excellent. We show that the combination of our u*-band and HSC data can lead to high-quality photometric redshifts at z = 0–3, and robust measurements of rest-frame UV on galaxies at 0.4 < z < 0.6 for distinguishing green-valley galaxies from star-forming and quiescent galaxies. We publicly release our reduced u*-band images and reference catalogs, which can be used readily for scientific studies.

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Boissay, Rozenn, Quentin A. Parker, David J. Frew, and Ivan Bojicic. "Planetary nebulae and their mimics: The MASH-MEN Project." Proceedings of the International Astronomical Union 7, S283 (July 2011): 316–17. http://dx.doi.org/10.1017/s1743921312011209.

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AbstractThe total number of true, likely and possible planetary nebulae (PN) now known in the Milky Way is about 3000, approximately twice the number known a decade ago. The new discoveries are a legacy of the recent availability of wide-field, narrowband imaging surveys, primarily in the light of Hα. The two most important are the AAO/UKST SuperCOSMOS Hα survey SHS and the Isaac Newton photometric Hα survey IPHAS, which are responsible for most of the new discoveries. A serious problem with previous PN catalogs is that several different kinds of astrophysical objects are able to mimic PN in some of their observed properties leading to significant contamination. These objects include H~II regions and Strömgren zones around young O/B stars, reflection nebulae, Wolf-Rayet ejecta, supernova remnants, Herbig-Haro objects, young stellar objects, B[e] stars, symbiotic stars and outflows, late-type stars, cataclysmic variables, low redshift emission-line galaxies, and even image/detector flaws. PN catalogs such as the Macquarie/AAO/Strasbourg Hα Planetary Nebula catalog (MASH) have been carefully vetted to remove these mimics using the wealth of new wide-field multi-wavelength data and our 100% follow-up spectroscopy to produce a compilation of new PN discoveries of high purity. During this process significant numbers of PN mimics have been identified. The aim of this project is to compile these MASH rejects into a catalog of Miscellaneous Emission Nebulae (MEN) and to highlight the most unusual and interesting examples. A new global analysis of these MEN objects is underway before publishing the MEN catalog online categorizing objects by type together with their spectra and multi-wavelength images.

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Linganna, SiddeswaraBargur, Subhashish Nath, Vijay Gogoi, Jita Baruah, and Bikram Sutradhar. "Behavioural and Emotional difficulties in School children during COVID 19 pandemic using narrowband dimensions of SDQ: Online survey from North? East India." Industrial Psychiatry Journal 31, no. 2 (2022): 207. http://dx.doi.org/10.4103/ipj.ipj_130_21.

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49

Lee, Janice C., Chun Ly, Lee Spitler, Ivo Labbé, Samir Salim, S. Eric Persson, Masami Ouchi, Daniel A. Dale, Andy Monson та David Murphy. "A Dual-Narrowband Survey for Hα Emitters at Redshift of 2.2: Demonstration of the Technique and Constraints on the Hα Luminosity Function1". Publications of the Astronomical Society of the Pacific 124, № 917 (липень 2012): 782–97. http://dx.doi.org/10.1086/666528.

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Placco, Vinicius M., Felipe Almeida-Fernandes, Anke Arentsen, Young Sun Lee, William Schoenell, Tiago Ribeiro, and Antonio Kanaan. "Mining S-PLUS for Metal-poor Stars in the Milky Way." Astrophysical Journal Supplement Series 262, no. 1 (August 19, 2022): 8. http://dx.doi.org/10.3847/1538-4365/ac7ab0.

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Анотація:

Abstract This work presents the medium-resolution (R ∼ 1500) spectroscopic follow-up of 522 low-metallicity star candidates from the Southern Photometric Local Universe Survey (S-PLUS). The objects were selected from narrowband photometry, taking advantage of the metallicity-sensitive S-PLUS colors. The follow-up observations were conducted with the Blanco and Gemini South telescopes, using the COSMOS and GMOS spectrographs, respectively. The stellar atmospheric parameters (T eff, log g , and [Fe/H]), as well as carbon and α-element abundances, were calculated for the program stars in order to assess the efficacy of the color selection. Results show that 92 − 3 + 2 % of the observed stars have [Fe/H] ≤ −1.0, 83 − 3 + 3 % have [Fe/H] ≤ −2.0, and 15 − 3 + 3 % have [Fe/H] ≤ −3.0, including two ultra metal-poor stars ([Fe/H] ≤ −4.0). The 80th percentile for the metallicity cumulative distribution function of the observed sample is [Fe/H] = −2.04. The sample also includes 68 carbon-enhanced metal-poor stars. Based on the calculated metallicities, further S-PLUS color cuts are proposed, which can increase the fractions of stars with [Fe/H] ≤ −1.0 and ≤ −2.0 to 98% and 88%, respectively. Such high success rates enable targeted high-resolution spectroscopic follow-up efforts, as well as provide selection criteria for fiber-fed multiplex spectroscopic surveys.

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Статті в журналах з теми "Narrowband survey"

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