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Journal articles on the topic 'Galaxies : à haute redshift'

Author: Grafiati

Published: 23 September 2022

Last updated: 31 October 2022

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1

Mickaelian, A. M., S. K. Balayan, and S. A. Hakopian. "The Byurakan-IRAS Galaxy (BIG) Sample: The Redshift Survey." International Astronomical Union Colloquium 184 (2002): 217–19. http://dx.doi.org/10.1017/s0252921100030724.

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AbstractThe Byurakan-IRAS Galaxy (BIG) sample (1967 galaxies) is based on optical identifications of IRAS PSC sources at δ>+61° and |b| >15° (FBS area). A redshift survey for brighter objects (B<18m) is being carried out with the Byurakan Observatory 2.6m, Special Observatory 6m, and Observatoire de Haute-Provence 1.93m telescopes. 213 objects have been observed, and redshifts in the range 0.008-0.173 have been measured. For this subsample, 15% of the objects are AGNs, and 15% are LIGs and ULIGs.

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Mickaelian, A. M. "Investigation of the Local Universe by Means of IRAS Galaxies." Symposium - International Astronomical Union 204 (2001): 69. http://dx.doi.org/10.1017/s0074180900225904.

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The Byurakan-IRAS galaxy (BIG) sample is based on optical identifications of IRAS PSC sources (Beichman, C. A. et al., eds. 1988, Infrared Astronomical Satellite (IRAS) Catalogs and Atlases: The Point Source Catalog, NASA RP–1190, Washington, DC). It makes use of the IR colours, DSS images, and the First Byurakan Spectral Survey (Markarian, B. E. et al. 1989, Commun. Special Astrophys. Obs., 62, 5).All IRAS sources in the region +61° < δ < 90° at high galactic latitudes (|b| >15°) in an area of 1487 deg2 have been revealed up to the limit of the IRAS survey. The BIG sample (Mickaelian, A. M. 2000, Afz, 43, 425 and references therein) consists of 1500 galaxies, including 870 that were previously known. A redshift survey for brighter objects is being carried out with the SAO (Russia) 6 m, Byurakan Observatory 2.6 m, and Observatoire de Haute Provence 1.93 m telescopes. Redshifts in the range of 0.009–0.173 have been measured. For fainter objects, including 30 empty fields corresponding to sources with IR colors typical of galaxies, deep imaging is being carried out to reveal faint objects and study their morphologies. These objects are candidate ULIRGs. Many are multiple galaxies and small groups. About half of the galaxies are radio sources, and a number are also X-ray sources. The IR luminosity may be due to normal star formation or triggered by interaction or active galactic nuclei (AGNs). The AGNs and interacting/merging systems among the nearest BIG objects are the most interesting cases: they provide understanding of the properties of activity, starburst, and interaction phenomena and their interrelation, thus allowing a study of the physics and evolution of galaxies in the Local Universe.

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Mickaelian, Areg M. "Galaxy Evolution Traced by Multiple Galaxies from the BIG Sample." Proceedings of the International Astronomical Union 2, S235 (August 2006): 225. http://dx.doi.org/10.1017/s1743921306006314.

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AbstractOptical identifications of all IRAS PSC sources at high galactic latitudes by means of the First Byurakan Survey (FBS) in the area with +61° < δ < +90° at galactic latitudes |b|>15° have been carried out with a total surface of 1487 deg2. 1577 sources have been optically identified, 1178 sources corresponding to galaxies. The BIG sample (Byurakan-IRAS Galaxies) was constructed of 1178 newly identified galaxies and 789 other IRAS galaxies in the same area, known before, altogether 1967 galaxies. Studies of the BIG objects include: spectroscopic follow-up for the brighter (<18m) objects; discovery and study of new AGN; discovery and study of new ULIRGs; deep imagery of the most interesting objects and the “empty fields”; 2D spectroscopy of interacting/merging systems; search for obscured IRAS galaxies (with the Spitzer Space Telescope), etc. The BIG objects are a rich source for new AGN, high-luminosity IR galaxies (hence, starburst activity), and interacting/merging systems. All these phenomena are crucial for understanding the galaxy evolution and their interrelation, as well as the triggering of the powerful IR radiation. In frame of the redshift survey of these galaxies, spectroscopic observations have been carried out for the BIG objects (including the pairs and multiples) by means of the Byurakan Astrophysical Observatory (BAO, Armenia) 2.6m, Special Astrophysical Observatory (SAO, Russia) 6m, and Observatoire de Haute Provence (OHP, France) 1.93m telescopes. It is shown that, without an exception, all double/multiple BIG systems are physical pairs or groups, and they are mostly interacting and/or merging systems. From the high IR luminosities derived from the observations, one can conclude that perhaps the ULIRG/HLIRG phenomenon is connected with galaxy interactions/merging. We find an evolution in luminosity function of these objects with respect to their redshift distribution.Existence of AGN among the multiple BIG objects provides a chance for study of the galaxy evolution in sense of interrelationship between the three phenomena: starburst, interactions/merging, and nuclear activity. We have shown (Mickaelian et al. 2001) that the maximum IR luminosity of a single spiral galaxy may not be larger than 1012 Solar luminosities. Hence, all high-L IRAS galaxies are interacting pairs/multiples or mergers. But what is the relation of the active nucleus to the starburst (i.e. IR) activity?

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Barger, Amy. "High-Redshift Galaxies." Symposium - International Astronomical Union 216 (2005): 309–24. http://dx.doi.org/10.1017/s0074180900196743.

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Mapping the history of star formation requires combining observations at many wavelengths. The most dramatic episodes of star formation occurred in high-redshift (z > 1) galaxies obscured by dust. These galaxies can be seen at submillimeter wavelengths. While these episodes clearly constitute much of the star formation in the universe, we still do not know the redshift distribution. Although progess has been made in determining the nature of the brightest members of the submillimeter population, these galaxies comprise only a tiny fraction of the submillimeter extragalactic background light. Optical star formation, by contrast, is well mapped but hard to interpret because of the problems of extinction. At recent times there is still substantial star formation, but it primarily takes place in small galaxies. This cosmic downsizing is paralleled by similar evolution in the properties of AGNs.

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Giovanelli, Riccardo, and Martha P. Haynes. "Redshift Surveys of Galaxies." Annual Review of Astronomy and Astrophysics 29, no. 1 (September 1991): 499–541. http://dx.doi.org/10.1146/annurev.aa.29.090191.002435.

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6

McCarthy, Patrick J. "High Redshift Radio Galaxies." Annual Review of Astronomy and Astrophysics 31, no. 1 (September 1993): 639–88. http://dx.doi.org/10.1146/annurev.aa.31.090193.003231.

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7

Salvaterra, Ruben, Andrea Ferrara, and Pratika Dayal. "Simulating high-redshift galaxies." Monthly Notices of the Royal Astronomical Society 414, no. 2 (May 25, 2011): 847–59. http://dx.doi.org/10.1111/j.1365-2966.2010.18155.x.

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8

Pelló, Roser, Daniel Schaerer, Johan Richard, Jean-Franc Le Borgne, Jean-Paul Kneib, Angela Hempel, Eiichi Egami, et al. "High-redshift lensed galaxies." Proceedings of the International Astronomical Union 2, no. 14 (August 2006): 250. http://dx.doi.org/10.1017/s1743921307010320.

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9

Miley, George. "High-Redshift Radio Galaxies." Highlights of Astronomy 10 (1995): 543–46. http://dx.doi.org/10.1017/s1539299600011990.

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Radio galaxies are unique cosmological probes. As with radio-loud quasars, the presence of luminous radio continuum and optical line emission enable radio galaxies to be observed and recognized at large distances, up to z = 4.2. However, unlike the situation for most quasars, their optical emission can be spatially resolved from the ground and studied in detail.Progress in detecting distant radio galaxies has been rapid in recent years due to the use of CCDs and the exploitation of new selection criteria. Now, more than 60 radio galaxies are known with z > 2. More than half of these have been found by our group by concentrating on radio sources with the steepest spectra, most of these in a “Key Programme” of the European Southern Observatory. Although several people contributed to this Key Programme, most of the work was done by Huub Röttgering, who presented his Ph.D thesis in January and Rob van Ojik, who succeededhim. Redshifts of 1.5 to 4 correspond to a time when the Universe was 10% -20% of its present age. This was a crucial period in history when galaxy formation must have been rampant. It corresponds to the AGN era, a two-billion year “delta function” in the population evolution of luminous quasars and radio galaxies, when their space-density rose to a value several hundred times larger than the present density before the species mysteriously and suddenly became almost extinct.

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Meisenheimer, K., H. Hippelein, and M. Neeser. "High Redshift Radio Galaxies." Symposium - International Astronomical Union 175 (1996): 571–76. http://dx.doi.org/10.1017/s0074180900081894.

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One hundred years after G. Marconi recorded radio waves over a distance of more than 1000 m, the most sensitive radio telescopes are able to detect the radio emission from light travel distances at least 1.4 × 1023 times greater. The electromagnetic waves from these distant objects are red shifted by Δλ/λ = z > 4. It is not the mere distance of high redshift objects which is fascinating, but rather the fact that one looks back into the early history of the universe by observing them: Objects at a redshift of 4 shined at a time when the universe had reached only about 1/5 of its present age.

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Dunlop, James S. "High Redshift Radio Galaxies." Symposium - International Astronomical Union 168 (1996): 79–87. http://dx.doi.org/10.1017/s0074180900109957.

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The potentially important role of jet-cloud interactions in determining the appearance of high-redshift radio galaxies is discussed and investigated via new 3-dimensional simulations of off-axis jet-cloud collisions. The results indicate that the most powerful radio sources are likely to be observed during or shortly after a jet-cloud interaction, and that such interactions can explain both the radio structures and the spatial association between optical and radio light found in powerful radio galaxies at high redshift. It is argued that, due to the radio-power dependence of such complicating effects, the optical-infrared colours and morphologies of very radio-luminous high-redshift galaxies can tell us essentially nothing about their evolutionary state. Either one must study much less radio-luminous sources in which the AGN-induced contamination is minimised, or one must attempt to determine what fraction of the baryonic mass of the radio galaxy has been converted into stars at the epoch of observation. Recent observations aimed at performing the latter experiment on two well-known high-redshift radio galaxies (4C 41.17 & B2 0902+34) are described. It is concluded that at present there exists no clear evidence that either of these famous galaxies is ‘primæval’; on the contrary, the continued low-dispersion of the infrared Hubble diagram atz> 2 points toward a much higher redshift of formation for elliptical galaxies.

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Bian, Fuyan, Lisa J. Kewley, Brent Groves, and Michael A. Dopita. "Local analogs of high-redshift galaxies: Metallicity calibrations at high-redshift." Proceedings of the International Astronomical Union 15, S352 (June 2019): 309–13. http://dx.doi.org/10.1017/s1743921320000800.

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AbstractWe study the metallicity calibrations in high-redshift galaxies using a sample of local analogs of high-redshift galaxies selected from the SDSS survey. Located in the same region on the BPT diagram as star-forming galaxies at z ∼ 2, these high-redshift analogs share the same ionized ISM conditions as high-redshift galaxies. We establish empirical metallicity calibrations between the direct gas-phase oxygen abundances and varieties of metallicity indicators in our local analogs using direct Te method. These new metallicity calibrations are the best means to measure the metallicity in high-redshift galaxies. There exist significant offsets between these new high-redshift metallicity calibrations and local calibrations. Such offsets are mainly driven by the evolution of the ionized ISM conditions from high-z to low-z.

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Bian, Fuyan, Lisa J. Kewley, Brent Groves, and Michael A. Dopita. "What drives the redshift evolution of strong emission line ratios?" Monthly Notices of the Royal Astronomical Society 493, no. 1 (January 29, 2020): 580–85. http://dx.doi.org/10.1093/mnras/staa259.

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ABSTRACT We study the physical mechanisms that cause the offset between low-redshift and high-redshift galaxies on the [O iii] λ5007/H β versus [N ii] λ6584/H α ‘Baldwin, Phillips & Terlevich’ (BPT) diagram using a sample of local analogues of high-redshift galaxies. These high-redshift analogue galaxies are selected from the Sloan Digital Sky Survey. Located in the same region on the BPT diagram as the ultraviolet selected galaxies at z ∼ 2, these high-redshift analogue galaxies provide an ideal local benchmark to study the offset between the local and high-redshift galaxies on the BPT diagram. We compare the nitrogen-to-oxygen ratio (N/O), the shape of the ionizing radiation field, and ionization parameters between the high-redshift analogues and a sample of local reference galaxies. The higher ionization parameter in the high-redshift analogues is the dominant physical mechanism driving the BPT offset from low- to high-redshift, particularly at high [N ii] λ6584/H α. Furthermore, the N/O ratio enhancement also plays a minor role to cause the BPT offset. However, the shape of the ionizing radiation field is unlikely to cause the BPT offset because the high-redshift analogues have a similar hard ionizing radiation field as local reference galaxies. This hard radiation field cannot be produced by the current standard stellar synthesis models. The stellar rotation and binarity may help solve the discrepancy.

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Li, I. H., H. K. C. Yee, B. C. Hsieh, D. G. Gilbank, and M. D. Gladders. "The Evolution of Galaxies and Groups in Cluster Environments at 0.3 < z < 0.6." Proceedings of the International Astronomical Union 2, S235 (August 2006): 220. http://dx.doi.org/10.1017/s1743921306006260.

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We investigate the dependence of galaxy populations on environment. Our samples are selected from the follow-up of Red-Sequence Cluster Survey (RCS) catalogs using wide-field BVRz' imaging for 60 intermediate redshift (0.3 < z < 0.6) clusters. Galaxy redshifts are estimated using an empirical photometric redshift technique with a training set of 3996 galaxies to z 1.4. To obtain photometric redshift probability density for each galaxy, we bootstrap the training set galaxies to estimate the fitting uncertainties and apply Monte-Carlo method to simulate galaxy magnitudes errors. In order to find galaxy groups using photometric redshift, we develop a modified friends-of-friends algorithm, ‘Probability Friends-of-Friends Algorithm (pFOF)’, where photometric redshift redshift probability densities of individual galaxies are used to determine member galaxies of a group. We calculate the red galaxy fraction to infer the evolutionary status of cluster galaxies and also for galaxies in groups selected in the same redshift space as the clusters.

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Mahdi, Hareth Saad. "The Bimodal Color Distribution of Galaxies at Redshift of z=0-0.15 from the Sloan Digital Sky Survey (SDSS)." Al-Mustansiriyah Journal of Science 30, no. 2 (September 30, 2019): 52. http://dx.doi.org/10.23851/mjs.v30i2.574.

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This work aims to use the color distribution of galaxies to differentiate between blue and red galaxies. The photometric data of 300000 galaxies at redshift of z = 0 – 0.15 were collected from the Sloan Digital Sky Survey (SDSS). Three redshift ranges were considered for the purpose of this work: 100000 galaxies at z = 0-0.05, 100000 galaxies at z = 0.05-0.1 and 100000 galaxies at z = 0.1-0.15. The color distributions for all redshift ranges were determined. The results have clearly shown that the color distributions for all redshift ranges are bimodal. One of the two peaks corresponds to the blue galaxies (young and star-forming galaxies), whereas the other peak corresponds to the red galaxies (old and non-star-forming galaxies). Therefore, the color distribution of galaxies can be considered as an efficient tool to distinguish between blue and red galaxies.

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Misquitta, Persis, Micah Bowles, Andreas Eckart, Madeleine Yttergren, Gerold Busch, Monica Valencia-S., and Nastaran Fazeli. "Interactions among intermediate redshift galaxies." Astronomy & Astrophysics 639 (July 2020): A30. http://dx.doi.org/10.1051/0004-6361/201937009.

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We present the properties of the central supermassive black holes and the host galaxies of the interacting object SDSS J134420.86+663717.8. We obtained optical long slit spectroscopy data from the Large Binocular Telescope using the Multi Object Double Spectrograph. Analysing the spectra revealed several strong broad and narrow emission lines of ionised gas in the nuclear region of one galaxy, whereas only narrow emission lines were visible for the second galaxy. The optical spectra were used to plot diagnostic diagrams, deduce rotation curves of the two galaxies, and calculate the masses of the central supermassive black holes. We find that the galaxy with broad emission line features has Seyfert 1 properties, while the galaxy with only narrow emission line features seems to be star-forming in nature. Furthermore, we find that the masses of the central supermassive black holes are almost equal at a few times 107 M⊙. Additionally, we present a simple N-body simulation to shed some light on the initial conditions of the progenitor galaxies. We find that for an almost orthogonal approach of the two interacting galaxies, the model resembles the optical image of the system.

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Malhotra, Sangeeta, and James E. Rhoads. "High-redshift Lyman-α galaxies." Proceedings of the International Astronomical Union 2, no. 14 (August 2006): 254. http://dx.doi.org/10.1017/s1743921307010368.

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A strong Lyman-α line enables relatively easy detection of high redshift galaxies. Lyman-α galaxies are now known from z = 3 to 6.6. No evolution is discerned in the Lyman-α line luminosity function in this redshift range. This implies that the intergalactic medium at z = 6 is at least 50% ionized over more than 50% of the volume. Recent continuum detections of these galaxies from HST, MMT and Spitzer are now allowing us to address questions about the nature of these Lyman-α emitters, their stellar populations and ages. We find that by and large the Lyman-α galaxies are young galaxies dominated by stellar populations that are less than 25 Myr old.

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Pettini, Max. "Disk Galaxies at High Redshift?" Proceedings of the International Astronomical Union 4, S254 (June 2008): 21–32. http://dx.doi.org/10.1017/s1743921308027348.

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AbstractThe successful implementation of integral field near-infrared spectrographs fed by adaptive optics is providing unprecedented views of gas motions within galaxies at redshifts z = 2 − 3, when the universe was forming stars at its peak rate. A complex picture of galaxy kinematics is emerging, with inflows, rotation within sometimes extended and nearly always thick disks, mergers, and galaxy-wide outflows all contributing to the variety of patterns seen. On the computational side, simulations of galaxy formation have reached a level of sophistication which can not only reproduce many of the properties of today's galaxies, but also throws new light on high redshift galaxies which are too faint to be detected directly, such as those giving rise to quasar absorption lines. In this brief review, I summarise recent progress in these areas.

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Pettini, Max, David L. King, Linda J. Smith, and Richard W. Hunstead. "Dust in High‐Redshift Galaxies." Astrophysical Journal 478, no. 2 (April 1997): 536–41. http://dx.doi.org/10.1086/303826.

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20

Pelló, R., D. Schaerer, J. Richard, J. F. Le Borgne, and J. P. Kneib. "Very High-Redshift Lensed Galaxies." Proceedings of the International Astronomical Union 2004, IAUS225 (July 2004): 373–86. http://dx.doi.org/10.1017/s1743921305002188.

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21

Scarpa, R., R. Falomo, and J. E. Pesce. "Redshift of southern radio galaxies." Astronomy and Astrophysics Supplement Series 116, no. 2 (April 1996): 295–300. http://dx.doi.org/10.1051/aas:1996115.

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22

Jaskot, Anne, and Sally Oey. "The Green Peas: Searching for LyC Emitters at Low Redshift." Proceedings of the International Astronomical Union 11, S319 (August 2015): 126. http://dx.doi.org/10.1017/s1743921315010054.

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AbstractThe escape fraction of Lyman continuum (LyC) radiation from galaxies remains one of the primary uncertainties in studies of reionization. However, few LyC-emitting galaxies are known. The recently identified, low-redshift “Green Pea” (GP) galaxies exhibit a number of similarities with high-redshift galaxies, and their optical emission lines suggest they may be some of the elusive LyC emitters. Recent HST COS and ACS observations of four GPs suggest further evidence for LyC escape and give new insights into the origins of Lyα and low-ionization UV lines in high-redshift galaxies. The Lyα emission and low-ionization emission and absorption lines provide a coherent physical picture of the neutral gas distribution in the GPs and may identify LyC emitters at high redshift. The rare, low-redshift GPs hint at possible factors that may enable LyC and Lyα escape from high-redshift galaxies.

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23

Arp, Halton. "Redshifts of New Galaxies." Symposium - International Astronomical Union 194 (1999): 347–55. http://dx.doi.org/10.1017/s007418090016228x.

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Observations increasingly demonstrate the spatial association of high redshift objects with larger, low redshift galaxies. These companion objects show a continuous range of physical properties - from very compact, high redshift quasars, through smaller active galaxies and finally to only slightly smaller companion galaxies of slightly higher redshift. The shift in energy distribution from high to low makes it clear that are seeing an empirical evolution from newly created to older, more normal galaxies.In order to account for the evolution of intrinsic redshift we must conclude that matter is initially born with low mass particles whose mass increase with time (age). This requires a physics which is nonlocal (Machian) and which is therefore more applicable to the cosmos than the Big Bang extrapolation of local physics. Ambartsumian's “superfluid” foresaw some of the properties of the new, low particle mass, protogalactic plasma which is required, demonstrating again the age-old lesson that open minded observation is much more powerful than theoretical assumptions.Since the ejected plasma, which preferentially emerges along the minor axis of the parent galaxy, develops into an entire galaxy, accretion disks cannot supply sufficient material. New matter must be created within a “white hole” rather than bouncing old matter off a “black hole”.

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Yoifoi, Ponlawat, and Wichean Kriwattanawong. "Galaxy evolution in different environments along redshift within the local universe z < 0.8." Journal of Physics: Conference Series 2145, no. 1 (December 1, 2021): 012002. http://dx.doi.org/10.1088/1742-6596/2145/1/012002.

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Abstract This study presents the evolution of the galaxies in different matter density along redshift within the local universe. A sample of 702,352 galaxies was collected from the Sloan Digital Sky Survey (SDSS). Under the limitation of the spectroscopic data, the appropriate photometric redshift was used to represent the spectroscopic redshift in the range of 0.0 ≤ z ≤ 0.8. Number density of galaxies, galaxy’s colors, and star formation activities are considered to describe the evolution of galaxies. In summary, the number density is not clearly different although the Dec and RA of the sky areas are disparate, but it steeply declines along the redshift direction. Considering the number density together with galaxies’ Hα emission line from spectroscopic data, we find that both equivalent of hydrogen alpha and Hα flux tend to decrease along the redshift, similar to the decreasing trend of the number density. Furthermore, the galaxy color trend is found to be redder as a function of the redshift for the magnitude range of -19 ≤ M g ≤ -17. It implies that the overview of the star formation activity of the fainter galaxies at the lower redshift tend to show higher than the ones at higher redshift.

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Yuan, Qi-Rong, Qiang-Qiang Dang, Peng-Fei Yan, Wei Chen, Zhong-Lue Wen, Jin-Lin Han, and Xu Zhou. "Correlation of morphological fraction with redshift in galaxy clusters." Proceedings of the International Astronomical Union 10, H16 (August 2012): 136. http://dx.doi.org/10.1017/s1743921314004979.

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AbstractBased on 187 galaxy clusters identified from the photometric redshifts of galaxies in the Cosmic Evolution Survey (COSMOS) field(Wen & Han 2011), cluster galaxies brighter than MV = -20.5 are classified into four categories according to their best-fitting templates of the spectral energy distributions (SEDs) provided by Ilbert et al. (2009): early-type (including elliptical and lenticular) galaxies (E+S0), spiral galaxies (S), irregular galaxies (Irr), and starbursts (SB). The fractions of these four SED types are presented as the functions of redshift in Figure 1. Fraction of each category varies remarkably with cluster redshift: fractions of normal galaxies (E+S0+S+Irr) tend to decrease with redshift, whilst the starburst proportion tends to increase with redshift. For the normal galaxies, there exists a sequence for the decreasing slopes of morphological fractions. Majority of the galaxies in high-redshift clusters (z > 1.0) are experiencing strong star-formation activities, which leads to a very high proportion of starburst.

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Shuntov, M., J. Pasquet, S. Arnouts, O. Ilbert, M. Treyer, E. Bertin, S. de la Torre, et al. "PhotoWeb redshift: boosting photometric redshift accuracy with large spectroscopic surveys." Astronomy & Astrophysics 636 (April 2020): A90. http://dx.doi.org/10.1051/0004-6361/201937382.

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Improving distance measurements in large imaging surveys is a major challenge to better reveal the distribution of galaxies on a large scale and to link galaxy properties with their environments. As recently shown, photometric redshifts can be efficiently combined with the cosmic web extracted from overlapping spectroscopic surveys to improve their accuracy. In this paper we apply a similar method using a new generation of photometric redshifts based on a convolution neural network (CNN). The CNN is trained on the SDSS images with the main galaxy sample (SDSS-MGS, r ≤ 17.8) and the GAMA spectroscopic redshifts up to r ∼ 19.8. The mapping of the cosmic web is obtained with 680 000 spectroscopic redshifts from the MGS and BOSS surveys. The redshift probability distribution functions (PDF), which are well calibrated (unbiased and narrow, ≤120 Mpc), intercept a few cosmic web structures along the line of sight. Combining these PDFs with the density field distribution provides new photometric redshifts, zweb, whose accuracy is improved by a factor of two (i.e., σ ∼ 0.004(1 + z)) for galaxies with r ≤ 17.8. For half of them, the distance accuracy is better than 10 cMpc. The narrower the original PDF, the larger the boost in accuracy. No gain is observed for original PDFs wider than 0.03. The final zweb PDFs also appear well calibrated. The method performs slightly better for passive galaxies than star-forming ones, and for galaxies in massive groups since these populations better trace the underlying large-scale structure. Reducing the spectroscopic sampling by a factor of 8 still improves the photometric redshift accuracy by 25%. Finally, extending the method to galaxies fainter than the MGS limit still improves the redshift estimates for 70% of the galaxies, with a gain in accuracy of 20% at low z where the resolution of the cosmic web is the highest. As two competing factors contribute to the performance of the method, the photometric redshift accuracy and the resolution of the cosmic web, the benefit of combining cosmological imaging surveys with spectroscopic surveys at higher redshift remains to be evaluated.

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Chisholm, J., S. Gazagnes, D. Schaerer, A. Verhamme, J. R. Rigby, M. Bayliss, K. Sharon, M. Gladders, and H. Dahle. "Accurately predicting the escape fraction of ionizing photons using rest-frame ultraviolet absorption lines." Astronomy & Astrophysics 616 (August 2018): A30. http://dx.doi.org/10.1051/0004-6361/201832758.

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The fraction of ionizing photons that escape high-redshift galaxies sensitively determines whether galaxies reionized the early Universe. However, this escape fraction cannot be measured from high-redshift galaxies because the opacity of the intergalactic medium is large at high redshifts. Without methods to measure the escape fraction of high-redshift galaxies indirectly, it is unlikely that we will know what reionized the Universe. Here, we analyze the far-ultraviolet (UV) H I (Lyman series) and low-ionization metal absorption lines of nine low-redshift, confirmed Lyman continuum emitting galaxies. We use the H I covering fractions, column densities, and dust attenuations measured in a companion paper to predict the escape fraction of ionizing photons. We find good agreement between the predicted and observed Lyman continuum escape fractions (within 1.4σ) using both the H I and ISM absorption lines. The ionizing photons escape through holes in the H I, but we show that dust attenuation reduces the fraction of photons that escape galaxies. This means that the average high-redshift galaxy likely emits more ionizing photons than low-redshift galaxies. Two other indirect methods accurately predict the escape fractions: the Lyα escape fraction and the optical [O III]/[O II] flux ratio. We use these indirect methods to predict the escape fraction of a sample of 21 galaxies with rest-frame UV spectra but without Lyman continuum observations. Many of these galaxies have low escape fractions (fesc ≤ 1%), but 11 have escape fractions >1%. Future studies will use these methods to measure the escape fractions of high-redshift galaxies, enabling upcoming telescopes to determine whether star-forming galaxies reionized the early Universe.

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Susa, Hajime, and Masayuki Umemura. "A Simulation of Galaxy Formation by Radiation-SPH." Symposium - International Astronomical Union 208 (2003): 323–30. http://dx.doi.org/10.1017/s0074180900207274.

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We investigate galaxy formation with Radiation-SPH simulations in order to find the effects of ultraviolet background radiation field on the star formation in the forming galaxies. We find the ultraviolet background radiation field can delay the star formation in protogalactic clouds, especially at low redshift (z < 2). This result suggests that galaxies formed at lower redshift tend to be late type galaxies, and early type galaxies tend to be formed at higher redshift.

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A Norman, Colin. "Star Formation at High Redshift." Australian Journal of Physics 45, no. 4 (1992): 389. http://dx.doi.org/10.1071/ph920389.

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The observations relevant to star formation at high redshift are reviewed including radio galaxies, quasars, IRAS objects, and QSO emission and absorption line regions. Low redshift counterparts associated with starburst galaxies are discussed. The relation of galaxy formation, starbursts, and active galaxies and quasars is briefly reviewed. The role of feedback in galaxy formation and massive star formation is briefly analysed.

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Moller, P., S. J. Warren, S. M. Fall, J. U. Fynbo, and P. Jakobsen. "Are High‐Redshift Damped Lyα Galaxies Lyman Break Galaxies?" Astrophysical Journal 574, no. 1 (July 20, 2002): 51–58. http://dx.doi.org/10.1086/340934.

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Byrd, Gene G., and Mauri J. Valtonen. "Redshift Asymmetries and the Missing Mass." Symposium - International Astronomical Union 124 (1987): 503–6. http://dx.doi.org/10.1017/s0074180900159455.

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We study the existence of missing mass in the outermost regions of galaxies not accessible to study by rotation curve methods. We consider binary galaxies, groups and clusters of galaxies. Arp has previously explained redshift asymmetries in pairs or groups with “non-Doppler redshifts”. Instead, we propose the asymmetries indicate contamination by optical pairs or by members which are not gravitationally bound to the group or pair. The group samples which are commonly used to justify very high missing mass values in spiral galaxies (>> the mass detected by rotation curves) also exhibit significant redshift asymmetries. From this and other information, we conclude that spiral galaxies do not possess very massive halos. Only the rare giant elliptical galaxies, such as the binary pair in the center of the Coma Cluster of galaxies, apparently possess extremely massive halos. Dynamical effects of such giants lead to overestimates of the mass of clusters. The evidence indicates that missing mass sufficient to close the universe is not concentrated in individual galaxies, groups or rich clusters.

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Daly, Ruth A., and Erick J. Guerra. "FRIIb Radio Galaxies, Cosmology, and Quintessence." Symposium - International Astronomical Union 201 (2005): 264–67. http://dx.doi.org/10.1017/s0074180900216343.

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FRIIb radio galaxies can be used as modified standard yardsticks to determine global cosmological parameters; the method is analogous to the use of supernovae type Ia as modified standard candles. FRIIb radio galaxies are observed to very high-redshift; the sources discussed here are fairly evenly distributed in redshift, with redshifts between zero and two. The sources can be used to determine the coordinate distance to high-redshift sources, and thus can constrain global cosmological parameters (just like the use of supernova type Ia to determine the coordinate distance, or luminosity distance, to high-redshift sources). Current constraints on global cosmological parameters and on quintessence obtained using FRIIb radio galaxies are presented.

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Appleton, P. N. "Collisional Ring Galaxies." Symposium - International Astronomical Union 186 (1999): 97–104. http://dx.doi.org/10.1017/s007418090011232x.

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Ring galaxies are believed to represent a special case of a collision between two galaxies, in which one of the galaxies impacts and passes through the center of another disk system (e.g. Lynds & Toomre 1976). Although rare, this kind of low orbital-angular-momentum collision leads to a recognizable structure, namely a luminous blue star-forming ring (Appleton & Marston 1997), which should be easily identifiable even at moderate redshift. Indeed, Lavery et al. (1996) have used this fact, and their relative rarity at low-redshift, to conclude that rings (and therefore presumably all collisions) are over-represented in deep HST fields.

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Zhu Xing-fen and Chu Yao-quan. "Periodic redshift distribution of quasars associated with low — redshift galaxies." Chinese Astronomy and Astrophysics 14, no. 4 (December 1990): 429–36. http://dx.doi.org/10.1016/0275-1062(90)90023-7.

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Kong, Xu, Jianhui Lian, Yulong Gao, Zuyi Chen, Guangwen Chen, Zesen Lin, and Haiyang Liu. "Dwarf galaxies at low and high redshift." Proceedings of the International Astronomical Union 14, S344 (August 2018): 437–45. http://dx.doi.org/10.1017/s174392131800652x.

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AbstractThe overwhelming majority of galaxies in the Universe are dwarf galaxies. But although they are important components in understanding galaxy evolution, these systems are typically too faint to be observed at high redshifts. However, we are able to obtain an unobscured view of early star formation and chemical enrichment in these galaxies at low redshift and low-redshift analogs at high redshift. In this talk, I will review the mass-metallicity relation, the mass-star formation rate relation of galaxies, the classifications of dwarf galaxies, and the importance of dwarf galaxies for both astronomy and physics. Then I will introduce some work in our group on connections among between different types of dwarf galaxies,the mass-metallicity relations and the main sequence relations of dwarf galaxies, using the deep optical and near infrared images and spectra of large dwarf galaxy sample. At the end, I will talk about some projects of dwarf galaxies we are working on, including the spectroscopic survey for compact dwarf galaxies using the LAMOST.

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Wilkinson, Aaron, Omar Almaini, Vivienne Wild, David Maltby, William G. Hartley, Chris Simpson, and Kate Rowlands. "From starburst to quiescence: post-starburst galaxies and their large-scale clustering over cosmic time." Monthly Notices of the Royal Astronomical Society 504, no. 3 (April 15, 2021): 4533–50. http://dx.doi.org/10.1093/mnras/stab965.

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ABSTRACT We present the first study of the large-scale clustering of post-starburst (PSB) galaxies in the high-redshift Universe (0.5 < z < 3.0). We select ∼4000 PSB galaxies photometrically, the largest high-redshift sample of this kind, from two deep large-scale near-infrared surveys: the UKIDSS Ultra Deep Survey Data Release 11 and the Cosmic Evolution Survey. Using angular cross-correlation techniques, we estimate the halo masses for this large sample of PSB galaxies and compare them with quiescent and star-forming galaxies selected in the same fields. We find that low-mass, low-redshift (0.5 < z < 1.0) PSB galaxies preferentially reside in very high mass dark matter haloes (Mhalo > 1014 M⊙), suggesting that they are likely to be infalling satellite galaxies in cluster-like environments. High-mass PSB galaxies are more weakly clustered at low redshifts, but they reside in higher mass haloes with increasing look-back time, suggesting strong redshift-dependent halo downsizing. These key results are consistent with previous results, suggesting that two main channels are responsible for the rapid quenching of galaxies. While high-redshift (z > 1) galaxies appear to be quenched by secular feedback mechanisms, processes associated with dense environments are likely to be the key driver of rapid quenching in the low-redshift Universe (z < 1). Finally, we show that the clustering of photometrically selected PSBs is consistent with them being direct descendants of highly dust-enshrouded submillimetre galaxies, providing tantalizing evidence for the oft-speculated evolutionary pathway from starburst to quiescence.

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Bian, Fuyan, Lisa J. Kewley, Michael A. Dopita, and Stephanie Juneau. "Local analogs of high-redshift galaxies: Interstellar medium conditions." Proceedings of the International Astronomical Union 11, S321 (March 2016): 333–35. http://dx.doi.org/10.1017/s1743921316009261.

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AbstractLocal analog galaxies play an important role in understanding the properties of high-redshift galaxies. We present a method to select a type of local analog that closely resembles the ionized interstellar medium conditions in high-redshift galaxies. These galaxies are selected based on their locations in the [O III]/Hβ versus [N II]/Hα nebular emission-line diagnostic diagram. The ionization parameters and electron densities in these analogs are comparable to those in z ≃ 2 − 3 galaxies, but higher than those in normal SDSS galaxies by ≃ 0.6 dex and ≃ 0.9 dex, respectively. We find that the high sSFR and SFR surface density can enhance the electron densities and the ionization parameters, but still cannot fully explain the difference in ISM condition between nearby galaxies and the local analogs/high-redshift galaxies.

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García, L. A. "THE PROPERTIES OF HIGH REDSHIFT GALAXIES." Revista Mexicana de Astronomía y Astrofísica 58, no. 1 (April 1, 2022): 83–97. http://dx.doi.org/10.22201/ia.01851101p.2022.58.01.07.

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This work studies the connection between the first galaxies and their hosting dark matter halos in the early Universe when reionization is concluding. Our numerical models (already presented in an earlier study) trace the star formation history at z = 4 - 8, the galaxy stellar mass function, the stellar-to-halo mass distribution, and other high redshift galaxies statistics. All these predictions are consistent with observations to date and with other high-resolution cosmological simulations. A key finding of this work is the robust estimate of the cosmic star formation history (through the implementation of galaxy and supernova winds and atomic and molecular cooling processes) and self-consistent chemical pollution of the intergalactic medium. The theoretical models are compatible with a faint-end slope of the galaxy luminosity function of α = −2 at the end of reionization.

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García, L. A. "THE PROPERTIES OF HIGH REDSHIFT GALAXIES." Revista Mexicana de Astronomía y Astrofísica 58, no. 1 (April 1, 2022): 83–97. http://dx.doi.org/10.22201/ia.01851101p.2022.58.01.07.

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This work studies the connection between the first galaxies and their hosting dark matter halos in the early Universe when reionization is concluding. Our numerical models (already presented in an earlier study) trace the star formation history at z = 4 - 8, the galaxy stellar mass function, the stellar-to-halo mass distribution, and other high redshift galaxies statistics. All these predictions are consistent with observations to date and with other high-resolution cosmological simulations. A key finding of this work is the robust estimate of the cosmic star formation history (through the implementation of galaxy and supernova winds and atomic and molecular cooling processes) and self-consistent chemical pollution of the intergalactic medium. The theoretical models are compatible with a faint-end slope of the galaxy luminosity function of α = −2 at the end of reionization.

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40

Steinhardt, Charles L., Christian Kragh Jespersen, and Nora B. Linzer. "Finding High-redshift Galaxies with JWST." Astrophysical Journal 923, no. 1 (December 1, 2021): 8. http://dx.doi.org/10.3847/1538-4357/ac2a2f.

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Abstract One of the primary goals for the upcoming James Webb Space Telescope is to observe the first galaxies. Predictions for planned and proposed surveys have typically focused on average galaxy counts, assuming a random distribution of galaxies across the observed field. The first and most-massive galaxies, however, are expected to be tightly clustered, an effect known as cosmic variance. We show that cosmic variance is likely to be the dominant contribution to uncertainty for high-redshift mass and luminosity functions, and that median high-redshift and high-mass galaxy counts for planned observations lie significantly below average counts. Several different strategies are considered for improving our understanding of the first galaxies, including adding depth, area, and independent pointings. Adding independent pointings is shown to be the most efficient both for discovering the single highest-redshift galaxy and also for constraining mass and luminosity functions.

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41

Wu, J. M., and T. Chiueh. "Strong Lensing on High‐Redshift Galaxies." Astrophysical Journal 639, no. 2 (March 10, 2006): 695–99. http://dx.doi.org/10.1086/499555.

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Phillipps, S., J. I. Davies, and M. J. Disney. "The visibility of high-redshift galaxies." Monthly Notices of the Royal Astronomical Society 242, no. 2 (April 1990): 235–40. http://dx.doi.org/10.1093/mnras/242.2.235.

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de Diego, José A., Jordi Cepa, Mario De Leo, and Ángel Bongiovanni. "High redshift galaxies through gravitational lensing." Journal of Physics: Conference Series 314 (September 22, 2011): 012119. http://dx.doi.org/10.1088/1742-6596/314/1/012119.

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Sharp, N. A. "Anomalous redshift companion galaxies - 0213-2836." Astrophysical Journal 297 (October 1985): 90. http://dx.doi.org/10.1086/163506.

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Sharp, N. A. "Anomalous redshift companion galaxies - NGC 7603." Astrophysical Journal 302 (March 1986): 245. http://dx.doi.org/10.1086/163986.

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Tapken, C., I. Appenzeller, S. Noll, S. Richling, J. Heidt, E. Meinköhn, and D. Mehlert. "Lyα emission in high-redshift galaxies." Astronomy & Astrophysics 467, no. 1 (February 27, 2007): 63–72. http://dx.doi.org/10.1051/0004-6361:20065825.

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Carilli, C. L., and F. Walter. "Cool Gas in High-Redshift Galaxies." Annual Review of Astronomy and Astrophysics 51, no. 1 (August 18, 2013): 105–61. http://dx.doi.org/10.1146/annurev-astro-082812-140953.

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Somerville, R. S., J. R. Primack, and S. M. Faber. "The nature of high-redshift galaxies." Monthly Notices of the Royal Astronomical Society 320, no. 4 (February 1, 2001): 504–28. http://dx.doi.org/10.1046/j.1365-8711.2001.03975.x.

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Cohen, Judith G., David W. Hogg, Michael A. Pahre, and Roger Blandford. "Strong Redshift Clustering of Distant Galaxies." Astrophysical Journal 462, no. 1 (May 1, 1996): L9—L12. http://dx.doi.org/10.1086/310020.

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Churchill, Christopher W., Glenn G. Kacprzak, and Charles C. Steidel. "MgII absorption through intermediate redshift galaxies." Proceedings of the International Astronomical Union 1, no. C199 (March 2005): 24–41. http://dx.doi.org/10.1017/s1743921305002401.

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