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Articles de revues sur le sujet « Ngc 454 »

Auteur : Grafiati
Publié le 9 mars 2023
Mis à jour le 10 mars 2023

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1

Plana, H., R. Rampazzo, P. Mazzei, A. Marino, Ph Amram et A. L. B. Ribeiro. « The NGC 454 system : anatomy of a mixed ongoing merger ». Monthly Notices of the Royal Astronomical Society 472, no 3 (14 août 2017) : 3074–92. http://dx.doi.org/10.1093/mnras/stx2091.

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Marchese, E., V. Braito, R. Della Ceca, A. Caccianiga et P. Severgnini. « NGC 454 : unveiling a new ‘changing look’ active galactic nucleus ». Monthly Notices of the Royal Astronomical Society 421, no 2 (9 février 2012) : 1803–12. http://dx.doi.org/10.1111/j.1365-2966.2012.20445.x.

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Stiavelli, M., N. Panagia, C. Marcella Carollo, M. Romaniello, I. Heyer et S. Gonzaga. « WFPC2 Observations of NGC 454 : An Interacting Pair of Galaxies ». Astrophysical Journal 492, no 2 (10 janvier 1998) : L135—L138. http://dx.doi.org/10.1086/311115.

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Iyomoto, N., K. Makishima, M. Tashiro, K. Matsushita, Y. Fukazawa, H. Kaneda et S. Osone. « Evidence for a Dramatic Activity Decline in the Nucleus of the Radio Galaxy Fornax A ». Symposium - International Astronomical Union 188 (1998) : 446. http://dx.doi.org/10.1017/s0074180900115955.

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Fornax A (NGC 1316) is a radio galaxy with prototypical double lobes. Feigelson et al. (1995 ApJ 449, L149) and Kaneda et al. (1995 ApJ 454, L13) detected inverse Compton X-rays for the first time from its radio lobes, and unambiguously derived the lobe magnetic field intensity of 2-4 μG. Accordingly, the radio-emitting electrons in the lobes are inferred to have a Lorentz factor of 104, and hence a synchrotron life time of ~108 yr. This means that Fornax A was highly active at least 108 years ago.
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Teixeira, Paula S., Charles J. Lada, Kenneth Wood, Thomas P. Robitaille et Kevin L. Luhman. « INFRARED SPECTROGRAPH CHARACTERIZATION OF A DEBRIS DISK AROUND AN M-TYPE STAR IN NGC 2547 ». Astrophysical Journal 700, no 1 (2 juillet 2009) : 454–59. http://dx.doi.org/10.1088/0004-637x/700/1/454.

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Fritzewski, D. J., S. A. Barnes, D. J. James, S. P. Järvinen et K. G. Strassmeier. « A detailed understanding of the rotation-activity relationship using the 300 Myr old open cluster NGC 3532 ». Astronomy & ; Astrophysics 656 (décembre 2021) : A103. http://dx.doi.org/10.1051/0004-6361/202140896.

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Context. The coeval stars of young open clusters provide insights into the formation of the rotation-activity relationship that elude studies of multi-age field populations. Aims. We measure the chromospheric activity of cool stars in the 300 Myr old open cluster NGC 3532 in concert with their rotation periods to study the mass-dependent morphology of activity for this transitional coeval population. Methods. Using multi-object spectra of the Ca II infrared triplet region obtained with the AAOmega spectrograph at the 4 m Anglo-Australian Telescope, we measure the chromospheric emission ratios RIRT′ for 454 FGKM cluster members of NGC 3532. Results. The morphology of activity against colour appears to be a near-mirror image of the cluster’s rotational behaviour. In particular, we identify a group of ‘desaturated transitional rotators’ that branches off from the main group of unsaturated FGK slow rotators, and from which it is separated by an ‘activity gap’. The few desaturated gap stars are identical to the ones in the rotational gap. Nevertheless, the rotation-activity diagram is completely normal. In fact, the relationship is so tight that it allows us to predict rotation periods for many additional stars. We then precisely determine these periods from our photometric light curves, allowing us to construct an enhanced colour-period diagram that represents 66% of the members in our sample. Our activity measurements show that all fast rotators of near-solar mass (F-G type) have evolved to become slow rotators, demonstrating that the absence of fast rotators in a colour-period diagram is not a detection issue but an astrophysical fact. We also identify a new population of low-activity stars among the early M dwarfs, enabling us to populate the extended slow rotator sequence in the colour-period diagram. Conclusions. The joint analysis of chromospheric activity and photometric time series data thus enables comprehensive insights into the evolution of the rotation and activity of stars during the transitional phase between the Pleiades and Hyades ages.
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Urbanik, M., M. Soida et R. Beck. « Magnetic Fields and the Interstellar Medium in Spiral Arms ». Symposium - International Astronomical Union 171 (1996) : 456. http://dx.doi.org/10.1017/s0074180900233743.

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We performed the high frequency radio studies of spiral galaxies using the 100 m MPIfR radio telescope at 10.55 GHz. Two objects: NGC 4254 and NGC 3627 possess perturbed spiral structures while two others, NGC 3521 and NGC 5055 are flocculent objects, lacking organized spiral patterns. NGC 3521 possesses also a peculiar dust lane. For NGC 4254, NGC 3627 and NGC 5055 deep polarization maps were made, for NGC 3521 the total power data only were analyzed (see Urbanik et al. 1989).
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Mayya, Y. D., et T. N. Rengarajan. « 7.9. Far-infrared emission and gas to dust ratio in discs and central regions of galaxies ». Symposium - International Astronomical Union 184 (1998) : 309–10. http://dx.doi.org/10.1017/s0074180900085053.

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We study the radial profiles of radio comtinuum (RC) and far-infrared (FIR) emissions and also the gas to dust ratio for a sample of 22 spiral galaxies. For this, we use the data from IRAS HiRES FIR maps, available VLA 20 cm maps and radial profile data available on neutral hydrogen (H) and molecular hydrogen (H2, derived from velocity integrated CO intensity). In order to have enough resolution with the 1-1.5 arcminute IRAS beam, the galaxies chosen were large sized and had a 60 μm flux density of more than 5 Jy. The sample consists of: NGC 628, NGC 2403, NGC 2841, NGC 2903, NGC 3079, NGC 3198, NGC 3627, NGC 3628, NGC 4192, NGC 4254, NGC 4303, NGC 4321, NGC 4501, NGC 4535, NGC 4569, NGC 4656, NGC 4736, NGC 5033, NGC 5055, NGC 6503, NGC 6946 and NGC 7331. For 13 of these galaxies information is also available on metallicity (z) and V band CCD maps.
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Plana, H., et J. Boulesteix. « Scanning Fabry-Perot observations of multiple profiles of faint and extended gas in the center of elliptical galaxies ». International Astronomical Union Colloquium 149 (1995) : 133–37. http://dx.doi.org/10.1017/s0252921100022806.

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AbstractSome elliptical galaxies possess an extended gaseous disk which is usually detected from Hα and [Nil] emission. 3-D ”Cigale” observations of two of these objects, NGC 1052 and NGC 404, show the evidence of peculiar dynamics a nd in one case multiple profiles of faint extended gas which are probably from different origins. In NGC 1052, the decoupled kinematics of the gas and the stellar systems favors the hypothesis of an external origin of the interstellar matter, while in NGC 404, coherence of the stars and gas axis, as well as the low gas velocity dispersion favors an inner origin of the gas from the stars themselves.
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Puerari, Ivânio, Margarita Valdez-Gutiérrez et Izbeth Hernández-López. « A Fourier Analysis of the Interacting Pair of Galaxies KPG 404 (NGC 5394/95) ». Symposium - International Astronomical Union 217 (2004) : 426–27. http://dx.doi.org/10.1017/s0074180900198109.

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We present a bi-dimensional Fourier analysis of near-infrared images of KPG 404 (NGC 5394/95). The 2D Fourier analysis shows that NGC 5394 is a H2β galaxy in the DP classification (Block & Puerari 1999). In contrast, NGC 5395 displays a very complex structure which needs a number of Fourier coefficients to be explained. A tightly wound m = 1 (DP class H1α) is the main structure, but other m = 1 and m = 2 coefficients (suggesting spiral arm modulation) are also present in the Fourier spectra. The complex structure of NGC 5395 also suggests a strong interaction in the pair. The m = 1 coefficients can represent a pseudo ring-type structure, resulting of a collision rather than a grazing passage. We conclude that the most probable scenario of the interaction in this pair should take into account a crossing of NGC 5394 through the disk of NGC 5395.
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Escudero, Carlos G., Favio R. Faifer, Analía V. Smith Castelli, Mark A. Norris et Juan C. Forte. « Field/isolated lenticular galaxies with high SN values : the case of NGC 4546 and its globular cluster system ». Monthly Notices of the Royal Astronomical Society 493, no 2 (10 février 2020) : 2253–70. http://dx.doi.org/10.1093/mnras/staa392.

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ABSTRACT We present a photometric study of the field lenticular galaxy NGC 4546 using Gemini/GMOS imaging in g′r′i′z′. We perform a 2D image decomposition of the surface brightness distribution of the galaxy using galfit, finding that four components adequately describe it. The subtraction of this model from our images and the construction of a colour map allow us to examine in great detail the asymmetric dust structures around the galactic centre. In addition, we perform a detailed analysis of the globular cluster (GC) system of NGC 4546. Using a Gaussian Mixture Model algorithm in the colour–colour plane, we detected hints of multiple groups of GC candidates: the classic blue and red subpopulations, a group with intermediate colours that present a concentrated spatial distribution towards the galaxy, and an additional group towards the red end of the colour distribution. We estimate a total GC population for NGC 4546 of 390 ± 60 members and specific frequency SN = 3.3 ± 0.7, which is relatively high compared to the typical value for galaxies of similar masses and environment. We suggest that the unusual GC population substructures were possibly formed during the interaction that led to the formation of the young ultra-compact dwarf (NGC 4546-UCD1) found in this system. Finally, we estimate the distance modulus of NGC 4546 by analysing its luminosity function, resulting in (m − M) = 30.75 ± 0.12 mag (14.1 Mpc).
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Alvarado, Franklin, Erich Wenderoth, Gonzalo Alcaino et William Liller. « Photoelectric UBVRI Sequences in the Magellanic Cloud Clusters NGC 458, NGC 1783, and NGC 1841 ». Astronomical Journal 110 (août 1995) : 646. http://dx.doi.org/10.1086/117551.

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Valdez-Gutiérrez, Margarita, Ivânio Puerari et Izbeth Hernández-López. « A Structural NIR Analysis of the Interacting Pair of Galaxies KPG 404 (NGC 5394/95) ». Symposium - International Astronomical Union 217 (2004) : 428–29. http://dx.doi.org/10.1017/s0074180900198110.

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We present near infrared observations in J, H and K' pass-bands of the interacting pair of galaxies KPG 404 (NGC 5394/95). We calculate total magnitudes, surface brightnesses and colour profiles. We present the growth curve to compare our photometry against earlier works in which circular aperture estimations were published. We also perform a structural (disk + bulge) analysis to get insight on the morphology of the pair. The disk+bulge fit shows that NGC 5394 (KPG 404A) is more compact than normal galaxies, while NGC 5395 (KPG 404B) is less concentrated. This suggests an interacting scenario in which NGC 5394 passes through the disk of NGC 5395 (a Cartwheel-type collision), rather than a passage as M51-type pairs.
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Bouchard, A., P. Prugniel, M. Koleva et M. Sharina. « Stellar population and kinematics of NGC 404 ». Astronomy and Astrophysics 513 (avril 2010) : A54. http://dx.doi.org/10.1051/0004-6361/200913137.

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15

Sage, L. J., et G. Galletta. « Counter-rotating molecular gas in NGC 4546 ». Astronomical Journal 108 (novembre 1994) : 1633. http://dx.doi.org/10.1086/117184.

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16

Dutta, Prasun, Ayesha Begum, Somnath Bharadwaj et Jayaram N. Chengalur. « Turbulence in the harassed galaxy NGC 4254 ». Monthly Notices of the Royal Astronomical Society : Letters 405, no 1 (12 avril 2010) : L102—L106. http://dx.doi.org/10.1111/j.1745-3933.2010.00869.x.

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17

Shatsova, R. B. « Stellar files for the NGC 457 cluster ». Astronomical & ; Astrophysical Transactions 7, no 2-3 (avril 1995) : 143–45. http://dx.doi.org/10.1080/10556799508205407.

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Piatti, Andres E., Eduardo Bica, Doug Geisler et Juan J. Claria. « Fundamental parameters of the LMC clusters NGC 1836, NGC 1860, NGC 1865, SL 444, LW 224 and SL 548 ». Monthly Notices of the Royal Astronomical Society 344, no 3 (septembre 2003) : 965–77. http://dx.doi.org/10.1046/j.1365-8711.2003.06887.x.

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19

Spetsieri, Z. T., A. Z. Bonanos, M. Yang, M. Kourniotis et D. Hatzidimitriou. « The HST Key Project galaxies NGC 1326A, NGC 1425, and NGC 4548 : New variable stars and massive star population ». Astronomy & ; Astrophysics 629 (22 août 2019) : A3. http://dx.doi.org/10.1051/0004-6361/201936074.

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Studies of the massive star population in galaxies beyond the Local Group are the key to understanding the link between their numbers and modes of star formation in different environments. We present the analysis of the massive star population of the galaxies NGC 1326A, NGC 1425, and NGC 4548 using archival images obtained with the Hubble Space Telescope Wide Field Planetary Camera 2 in the F555W and F814W filters. Through high-precision point spread function fitting photometry for all sources in the three fields, we identified 7640 candidate blue supergiants, 2314 candidate yellow supergiants, and 4270 candidate red supergiants. We provide an estimate of the ratio of blue to red supergiants for each field as a function of galactocentric radius. Using Modules for Experiments in Stellar Astrophysics (MESA) at solar metallicity, we defined the luminosity function and estimated the star formation history of each galaxy. We carried out a variability search in the V and I filters using three variability indexes: the median absolute deviation, the interquartile range, and the inverse von Neumann ratio. This analysis yielded 243 new variable candidates with absolute magnitudes ranging from MV = −4 to −10 mag. We classified the variable stars based on their absolute magnitude and their position on the color–magnitude diagram using the MESA evolutionary tracks at solar metallicity. Our analysis yielded 8 candidate variable blue supergiants, 12 candidate variable yellow supergiants, 21 candidate variable red supergiants, and 4 candidate periodic variables.
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Binder, B., B. F. Williams, M. Eracleous, A. C. Seth, J. J. Dalcanton, E. D. Skillman, D. R. Weisz, S. F. Anderson, T. J. Gaetz et P. P. Plucinsky. « A DEEPCHANDRAVIEW OF THE NGC 404 CENTRAL ENGINE ». Astrophysical Journal 737, no 2 (8 août 2011) : 77. http://dx.doi.org/10.1088/0004-637x/737/2/77.

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Broughton, Edward I., Gary D. Steinberg, Michael Roger Harrison, Julia Braverman, Dena H. Jaffe, Oliver Will, Steven S. Senglaub, Kristen King-Concialdi et Kathleen Beusterien. « Effect of neoadjuvant chemotherapy (NAC) on patient preferences for adjuvant treatment in muscle-invasive urothelial carcinoma (MIUC) : A multi-country discrete choice experiment (DCE). » Journal of Clinical Oncology 40, no 6_suppl (20 février 2022) : 454. http://dx.doi.org/10.1200/jco.2022.40.6_suppl.454.

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454 Background: Patient preference is an important factor in selecting appropriate treatment choices. Although underutilized, the standard of care for MIUC is with NAC, whereas evidence for adjuvant therapy is less clear. With the introduction of novel adjuvant treatments such as immune checkpoint inhibitors, treatment options are expected to expand. This study examines whether preferences for adjuvant therapy is impacted in MIUC patients receiving NAC. Methods: A cross-sectional, web-based survey included patients ≥ 18 years old who self-reported being diagnosed with MIUC and underwent radical cystectomy or nephroureterectomy without recurrence. Patients were recruited from the US, UK, Canada, France, and Germany (May–Sep 2021). A DCE using 2 adjuvant treatment profiles included 8 attributes: cancer-free survival, overall survival (OS), hypothyroidism requiring life-long hormone therapy, risk of a serious adverse event (requiring medical intervention/possible hospitalization), nausea, fatigue, diarrhea, and a dosing regimen (frequency of treatment and monitoring); an opt-out option of no treatment was also shown. Patients were grouped according to self-reported receipt of NAC. Descriptive statistics and hierarchical Bayesian logistic model with estimated preference weights were used. Relative importance estimates (mean ± standard error), or how much the attribute ranges accounted for the variation in preferences, were computed for each attribute. Bivariate comparisons used t-tests. Results: This interim analysis identified 205 patients (70.7% of target sample; US, n = 99; Germany, n = 60; UK, n = 31; Canada, n = 14; France, n = 1). Of 82 patients (40.0%) receiving NAC, 32.7% were patients > 65 years and 55.1% were male; receipt of NAC did not differ by age ( P = 0.248) or sex ( P = 0.731). Patients were willing to accept increased risk in toxicities for increased treatment efficacy. Specifically, mean relative importance of treatment attributes showed that difference in median OS (25 months compared to 78 months) was most important (34.6% ± 1.6), although less so for those who did not receive NAC (30.2% ± 2.4 vs 37.5% ± 2.0; P = 0.022). Patients chose an adjuvant treatment option over ‘no treatment’ 91% of the time, with similar findings by NAC status. Conclusions: Preliminary data indicates that receipt of NAC impacts preferences for adjuvant treatment attributes. However, regardless of these attributes, patients still preferred adjuvant treatment over none. These results suggest that providing standard of care NAC does not reduce patient preference for adjuvant therapy; rather, patient preferences for adjuvant treatment attributes vary by treatment history, with implications for improving quality of care and outcomes.
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Vollmer, B., W. Huchtmeier et W. van Driel. « NGC 4254 : a spiral galaxy entering the Virgo cluster ». Astronomy & ; Astrophysics 439, no 3 (12 août 2005) : 921–33. http://dx.doi.org/10.1051/0004-6361:20041350.

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Sofue, Yoshiaki, Jin Koda, Hiroyuki Nakanishi et Makoto Hidaka. « The Virgo High-Resolution CO Survey : III. NGC 4254 ». Publications of the Astronomical Society of Japan 55, no 1 (25 février 2003) : 75–86. http://dx.doi.org/10.1093/pasj/55.1.75.

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Chyży, Krzysztof T., Rainer Beck et Stanisław Ryś. « Star formation activity in the cluster spiral NGC 4254 ». Proceedings of the International Astronomical Union 2, S237 (août 2006) : 402. http://dx.doi.org/10.1017/s1743921307001901.

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AbstractWith sensitive radio observations of a Virgo Cluster spiral NGC 4254 we are able to decompose thermal and synchrotron radio emission and, based on the thermal component, construct the SFR distribution within the galaxy, unaffected by dust extinction. The mean SFR per unit area is several times higher than in other galaxies of similar Hubble type. Contrary to other Virgo spirals the SFR distribution is not spatially truncated, in concordance with the observed weak HI deficiency. We propose that the SFR enhancement and the observed disturbed morphology of this galaxy can be attributed to tidal triggering by another nearby cluster member.
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Cepa, J., B. Vila, N. Nakai, K. Kohno et R. Kawabe. « 5.15. Star formation and molecular gas in NGC 404 ». Symposium - International Astronomical Union 184 (1998) : 241–42. http://dx.doi.org/10.1017/s0074180900084771.

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The last decade has brought about a completely different picture of elliptical galaxies. The once considered completely inert systems have revealed the presence of fair amount of dust, cool and cold gas, and undergoing star formation. The current statistics is that 80% of elliptical galaxies have detectable cool gas components, and as many as 60% have ionized gas (Knapp et al. 1989, Goudfrooij et al. 1994). Several single-dish CO surveys have been reported in the literature, allowing the deduction of several general properties of the molecular gas in early-type galaxies (Sage & Wrobel 1989, Lees et al. 1991, Wiklind et al. 1995).
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Tikhonov, N. A., O. A. Galazutdinova et A. Aparicio. « Stellar content of NGC 404 – The nearest S0 Galaxy ». Astronomy & ; Astrophysics 401, no 3 (avril 2003) : 863–72. http://dx.doi.org/10.1051/0004-6361:20021819.

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Yamada, Rin I., Rei Enokiya, Hidetoshi Sano, Shinji Fujita, Mikito Kohno, Daichi Tsutsumi, Atsushi Nishimura, Kengo Tachihara et Yasuo Fukui. « A kinematic analysis of the CO clouds toward a reflection nebula NGC 2023 observed using the Nobeyama 45 m telescope : Further evidence for a cloud–cloud collision in the Orion region ». Publications of the Astronomical Society of Japan 73, no 4 (28 juin 2021) : 880–93. http://dx.doi.org/10.1093/pasj/psab050.

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Abstract We performed fully sampled J = 1–0 line observations of 12CO and 13CO toward the reflection nebula NGC 2023 using the Nobeyama 45 m telescope. It covered the entire NGC 2023 region with angular and velocity resolutions of 19″ corresponding to 0.04 pc and 0.33 km s−1, respectively. We analyzed the data focusing on gas dynamics and revealed two velocity components, each with a mass of $\sim\! 3000 \mbox{$\, {M}_\odot $}$, at radial velocities of 10 and 12 km s−1. These components show spatially complementary distributions and are connected in velocity, both of which are the typical signatures of cloud–cloud collision (CCC). Although previous studies favored a scheme of triggering by the H ii region of IC 434, our results show that the effect of the H ii region is limited only to the surface of the molecular cloud, and does not contribute to the entire gas compression and the overall star formation. Comparing the present results with those for neighboring NGC 2024, we find that their active star formation can be explained by a single CCC event. We suggest that the 10 and 12 km s−1 clouds collided ∼0.4 Myr ago, which is common to the regions, but triggered the B1.5V-type star HD 37903 as well as ∼20 low-mass stars in NGC 2023, and ∼20 OB stars in NGC 2024. The column density in NGC 2023 is two to three times lower than that of NGC 2024, which may result in the different star formation activity suggested by the trend of ∼50 other CCC-triggered star-forming regions in the literature.
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Aoki, K., G. Kosugi, M. Yoshida, H. Ohtani et A. S. Wilson. « 3.13. Outflow in the Seyfert galaxy NGC 7319 ». Symposium - International Astronomical Union 184 (1998) : 115–16. http://dx.doi.org/10.1017/s0074180900084266.

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Aoki et al. (1996) found outflowing gas in the Seyfert galaxy NGC 7319. The velocity of the outflow comes up to 500 km s−1 and its extent is 4 kpc. This outflow is one of the largest outflowing phenomenon that have ever been found in Seyfert galaxies. The radio emission found by van der Hulst & Rots (1981) aligns the outflowing gas. It suggests the radio emission has relation to the outflow. We have made higher resolution radio imaging of NGC 7319 with VLA to study in detail relation of radio emission to outflowing gas. These radio images have been compared to Hubble Space Telescope (HST) archival broad-band WFPC2 image. The systemic velocity 6740 km s−1 (Aoki et al. 1996) gives a distance of 90 Mpc for NGC 7319 assuming a Hubble constant H0=75 km s−1 Mpc−1. Thus 1″ corresponds to 450 pc.
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Bianchi, S., M. Murgia, A. Melis, V. Casasola, F. Galliano, F. Govoni, A. P. Jones et al. « Searching for anomalous microwave emission in nearby galaxies ». Astronomy & ; Astrophysics 658 (février 2022) : L8. http://dx.doi.org/10.1051/0004-6361/202142684.

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Aims. We observed four nearby spiral galaxies (NGC 3627, NGC 4254, NGC 4736, and NGC 5055) in the K band with the 64-m Sardinia Radio Telescope, with the aim of detecting anomalous microwave emission (AME), a radiation component presumably due to spinning dust grains, which has been observed thus far in the Milky Way and only in a handful of other galaxies (most notably, M 31). Methods. We mapped the galaxies at 18.6 and 24.6 GHz and studied their global photometry together with other radio-continuum data from the literature in order to find AME as emission in excess of the synchrotron and thermal components. Results. We only found upper limits for AME. These nondetections, and other upper limits in the literature, are nevertheless consistent with the average AME emissivity from a few detections: it is ϵ30 GHzAME = 2.4 ± 0.4 × 10−2 MJy sr−1 (M⊙ pc−2)−1 in units of dust surface density (equivalently, 1.4 ± 0.2 × 10−18 Jy sr−1 (H cm−2)−1 in units of H column density). We finally suggest searching for AME in quiescent spirals with relatively low radio luminosity, such as M 31.
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Zhang, X. B., C. Q. Luo et J. N. Fu. « B-TYPE VARIABLES IN THE YOUNG OPEN CLUSTER NGC 457 ». Astronomical Journal 144, no 3 (13 août 2012) : 86. http://dx.doi.org/10.1088/0004-6256/144/3/86.

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Menezes, Roberto B., João E. Steiner, Tiago V. Ricci et Alexandre S. Oliveira. « The nature of the LINER in the galaxy NGC 404 ». Proceedings of the International Astronomical Union 5, S262 (août 2009) : 390–91. http://dx.doi.org/10.1017/s1743921310003364.

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AbstractNGC 404, at a distance of 3.4 Mpc, is the nearest S0 galaxy. This galaxy harbors a LINER; however, since the spectrum does not show a broad Hα emission, it is not certain that this LINER is a low luminosity AGN and its nature is still an open question. HST observations show the existence of stellar populations with an age of 3 × 108 years in the galactic bulge and with an age of 6–15 × 109 years in the galactic disk. In this work, we present an analysis of the data cube of NGC 404 obtained with the IFU (Integral Field Unity) of the GMOS (Gemini Multi-Object Spectrograph) on the Gemini North telescope.
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32

Topasna, Gregory A., Eryn A. Daman et Nadia T. Kaltcheva. « Interstellar Polarization and Extinction towards the Open Cluster NGC 457 ». Publications of the Astronomical Society of the Pacific 129, no 980 (15 août 2017) : 104201. http://dx.doi.org/10.1088/1538-3873/aa7f6c.

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33

Haasler, D., V. M. Rivilla, S. Martín, J. Holdship, S. Viti, N. Harada, J. Mangum et al. « First extragalactic detection of a phosphorus-bearing molecule with ALCHEMI : Phosphorus nitride (PN) ». Astronomy & ; Astrophysics 659 (mars 2022) : A158. http://dx.doi.org/10.1051/0004-6361/202142032.

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Context. Phosphorus (P) is a crucial element for life given its central role in several biomolecules. P-bearing molecules have been discovered in different regions of the Milky Way, but not yet towards an extragalactic environment. Aims. We searched for P-bearing molecules outside the Milky Way towards the nearby starburst Galaxy NGC 253. Methods. Using observations from the ALMA Comprehensive High-resolution Extragalactic Molecular Inventory (ALCHEMI) project, we used the MAdrid Data CUBe Analysis package to model the emission of P-bearing molecules assuming local thermodynamic equilibrium (LTE) conditions. We also performed a non-LTE analysis using SpectralRadex. Results. We report the detection of a P-bearing molecule, phosphorus nitride (PN), for the first time in an extragalactic environment, towards two giant molecular clouds (GMCs) of NGC 253. The LTE analysis yields total PN beam-averaged column densities N = (1.20 ± 0.09) × 1013 cm−2 and N = (6.5 ± 1.6) × 1012 cm−2, which translate into abundances with respect to H2 of χ = (8.0 ± 1.0) × 10−12 and χ = (4.4 ± 1.2) × 10−12. We derived a low excitation temperature of Tex = (4.4 ± 1.3) K towards the GMC with the brightest PN emission, which indicates that PN is sub-thermally excited. The non-LTE analysis results in column densities consistent with the LTE values. We also searched for other P-bearing molecules (PO, PH3, CP, and CCP), and upper limits were derived. The derived PO/PN ratios are < 1.3 and < 1.7. The abundance ratio between PN and the shock-tracer SiO derived towards NGC 253 follows the same trend previously found towards Galactic sources. Conclusions. Comparison of the observations with chemical models indicates that the derived molecular abundances of PN in NGC 253 can be explained by shock-driven chemistry followed by cosmic-ray-driven photochemistry.
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Rengel, Miriam, Klaus Hodapp et Jochen Eislöffel. « SK 1 : A possible case of triggered star formation in perseus ». Proceedings of the International Astronomical Union 2, S237 (août 2006) : 217–21. http://dx.doi.org/10.1017/s1743921307001500.

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AbstractAccording to a triggered star formation scenario (e.g. Martin-Pintado & Cernicharo 1987) outflows powered by young stellar objects shape the molecular clouds, can dig cavities, and trigger new star formation. NGC 1333 is an active site of low- and intermediate star formation in Perseus and is a suggested site of self-regulated star formation (Norman & Silk 1980). Therefore it is a suitable target for a study of triggered star formation (e.g. Sandell & Knee 2001, SK1). On the other hand, continuum sub-mm observations of star forming regions can detect dust thermal emission of embedded sources (which drive outflows), and further detailed structures.Within the framework of our wide-field mapping of star formation regions in the Perseus and Orion molecular clouds using SCUBA at 850 and 450 μm, we mapped NCG 1333 with an area of around 14′× 21′. The maps show more structure than the previous maps of the region observed in sub-mm. We have unveiled the known embedded SK 1 source (in the dust shell of the SSV 13 ridge) and detailed structure of the region, among some other young protostars.In agreement with the SK 1 observations, our map of the region shows lumpy filaments and shells/cavities that seem to be created by outflows. The measured mass of SK 1 (~0.07 M) is much less than its virial mass (~0.2-1 M). Our observations support the idea of SK 1 as an event triggered by outflow-driven shells in NGC 1333 (induced by an increase in gas pressure and density due to radiation pressure from the stellar winds that have presumably created the dust shell). This kind of evidences provides a more thorough understanding of the star formation regulation processes.
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Stanke, Th, H. G. Arce, J. Bally, P. Bergman, J. Carpenter, C. J. Davis, W. Dent et al. « The APEX Large CO Heterodyne Orion Legacy Survey (ALCOHOLS) ». Astronomy & ; Astrophysics 658 (février 2022) : A178. http://dx.doi.org/10.1051/0004-6361/201937034.

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Context. The Orion molecular cloud complex harbours the nearest Giant Molecular Clouds (GMCs) and the nearest site of high-mass star formation. Its young star and protostar populations are thoroughly characterized. The region is therefore a prime target for the study of star formation. Aims. Here, we verify the performance of the SuperCAM 64 pixel heterodyne array on the Atacama Pathfinder Experiment (APEX). We give a descriptive overview of a set of wide-field CO(3–2) spectral line cubes obtained towards the Orion GMC complex, aimed at characterizing the dynamics and structure of the extended molecular gas in diverse regions of the clouds, ranging from very active sites of clustered star formation in Orion B to comparatively quiet regions in southern Orion A. In a future publication, we will characterize the full population of protostellar outflows and their feedback over an entire GMC. Methods. We present a 2.7 square degree (130 pc2) mapping survey in the 12CO(3–2) transition, obtained using SuperCAM on APEX at an angular resolution of 19′′ (7600 AU or 0.037 pc at a distance of 400 pc), covering the main sites of star formation in the Orion B cloud (L 1622, NGC 2071, NGC 2068, Ori B9, NGC 2024, and NGC 2023), and a large patch in the southern part of the L 1641 cloud in Orion A. Results. We describe CO integrated line emission and line moment maps and position-velocity diagrams for all survey fields and discuss a few sub-regions in some detail. Evidence for expanding bubbles is seen with lines splitting into double components, often in areas of optical nebulosities, most prominently in the NGC 2024 H II region, where we argue that the bulk of the molecular gas is in the foreground of the H II region. High CO(3–2)/CO(1–0) line ratios reveal warm CO along the western edge of the Orion B cloud in the NGC 2023 & NGC 2024 region facing the IC 434 H II region. We see multiple, well separated radial velocity cloud components towards several fields and propose that L 1641-S consists of a sequence of clouds at increasingly larger distances. We find a small, seemingly spherical cloud, which we term “Cow Nebula” globule, north of NGC 2071. We confirm that we can trace high velocity line wings out to the “extremely high velocity” regime in protostellar molecular outflows for the NGC 2071-IR outflow and the NGC 2024 CO jet, and identify the protostellar dust core FIR4 (rather than FIR5) as the true driving source of the NGC 2024 monopolar outflow.
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Baloković, M., A. Comastri, F. A. Harrison, D. M. Alexander, D. R. Ballantyne, F. E. Bauer, S. E. Boggs et al. « THENuSTARVIEW OF NEARBY COMPTON-THICK ACTIVE GALACTIC NUCLEI : THE CASES OF NGC 424, NGC 1320, AND IC 2560 ». Astrophysical Journal 794, no 2 (30 septembre 2014) : 111. http://dx.doi.org/10.1088/0004-637x/794/2/111.

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37

Bettoni, D., G. Galletta et T. Oosterloo. « Stellar and gas kinematics of NGC 4546, the double-spin SB0* ». Monthly Notices of the Royal Astronomical Society 248, no 3 (1 février 1991) : 544–54. http://dx.doi.org/10.1093/mnras/248.3.544.

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38

Moles, Mariano, Isabel Marquez, Josefa Masegosa, Ascension del Olmo, Jaime Perea et Halton Arp. « Testing for interaction between the galaxies NGC 450 and UGC 807 ». Astrophysical Journal 432 (septembre 1994) : 135. http://dx.doi.org/10.1086/174555.

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39

Lloyd, B. D. L., P. A. J. Jones et R. F. H. Haynes. « Observations of the radio jets in NGC 5090 (PKS B1318 -- 434) ». Monthly Notices of the Royal Astronomical Society 279, no 4 (11 avril 1996) : 1197–209. http://dx.doi.org/10.1093/mnras/279.4.1197.

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40

Galletta, G. « Detection of retrograde gas streaming in the SB0 galaxy NGC 4546 ». Astrophysical Journal 318 (juillet 1987) : 531. http://dx.doi.org/10.1086/165389.

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41

M. Gilbert, Andrea, et James R. Graham. « Kinematic Masses of Super Star Clusters in NGC 1569 ». Symposium - International Astronomical Union 207 (2002) : 471–73. http://dx.doi.org/10.1017/s0074180900224248.

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We summarize recent results from our study of the massive young super star clusters (SSCs) in the dwarf galaxy NGC 1569, and present new high-resolution NIRSPEC spectra that permit the measurement of a cluster's intrinsic stellar velocity dispersion. Thus we derive kinematic masses for the two brightest SSCs: 2.3 × 105 Msun for SSC B, and 3.9 × 105 and 4.4 × 105 Msun for the two components of SSC A.
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42

Schilke, Peter, et Malcolm Walmsley. « 15NH3 millimasers toward NGC 7538—IRS 1 ». Symposium - International Astronomical Union 147 (1991) : 489–90. http://dx.doi.org/10.1017/s0074180900240126.

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Ammonia towards the UCHII—region NGC 7538—IRS 1 shows an extremely hot component observed in absorption in several transitions and a so far unexplained (9,6) maser (see Fig. 1). This source is the only known source in the Galaxy where the 141 GHz line (1450 K above ground) of vibrationally excited Ammonia is seen in absorption (Schilke et al. 1990). An additional unique feature is the 15NH3(3,3) maser observed by Mauersberger et al. (1986) in Effelsberg and by Johnston et al. (1989) with the VLA. There are theoretical models to explain such a maser (see e.g. Flower, Offer and Schilke 1990) in low density regions where ortho-H2 is underabundant. In this study, our aim was to investigate 15NH3 in more detail. We succeeded in observing the (1,1) and (2,2) lines of 15NH3 in absorption and, surprisingly, the (4,3) and (4,4) lines in emission (see Fig. 1).
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43

Schilke, Peter, et Malcolm Walmsley. « 15NH3 millimasers toward NGC 7538—IRS 1 ». Symposium - International Astronomical Union 147 (1991) : 489–90. http://dx.doi.org/10.1017/s0074180900199504.

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Ammonia towards the UCHII—region NGC 7538—IRS 1 shows an extremely hot component observed in absorption in several transitions and a so far unexplained (9,6) maser (see Fig. 1). This source is the only known source in the Galaxy where the 141 GHz line (1450 K above ground) of vibrationally excited Ammonia is seen in absorption (Schilke et al. 1990). An additional unique feature is the 15NH3(3,3) maser observed by Mauersberger et al. (1986) in Effelsberg and by Johnston et al. (1989) with the VLA. There are theoretical models to explain such a maser (see e.g. Flower, Offer and Schilke 1990) in low density regions where ortho-H2 is underabundant. In this study, our aim was to investigate 15NH3 in more detail. We succeeded in observing the (1,1) and (2,2) lines of 15NH3 in absorption and, surprisingly, the (4,3) and (4,4) lines in emission (see Fig. 1).
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44

Ikegame, Ko, Keiichi Hatakeyama, Masanori Terashima, Takashi Sugino, Daisuke Aizawa, Kenichiro Furukawa, Keiichi Fujiya, Yutaka Tanizawa, Etsuro Bando et Ken Yamaguchi. « Molecular profiling of gastric neuroendocrine carcinomas. » Journal of Clinical Oncology 41, no 4_suppl (1 février 2023) : 451. http://dx.doi.org/10.1200/jco.2023.41.4_suppl.451.

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451 Background: Reports of comprehensive genetic analysis of gastric neuroendocrine carcinoma (G-NEC) are limited, and few have described the tumorigenesis of G-NEC. G-NEC usually has NEC and adenocarcinoma components and is considered to have a common origin in gastric adenocarcinoma because these two tumors share common pathogenic mutations and loss of heterozygosity. However, G-NEC without adenocarcinoma also exists, and it may have a different mechanism of tumorigenesis than that of G-NEC with adenocarcinoma. This study aimed to elucidate the tumorigenesis of G-NEC by focusing on the percentage of NEC component, using comprehensive genetic analysis. Methods: Of the 698 patients who had undergone gastrectomy for gastric cancer between January 2014 and March 2019, this study included 13 patients with G-NEC. Comprehensive genetic analysis using whole-exome sequencing, deep sequencing using a target gene panel, and microarray analysis were performed. NEC was classified according to the 2010 WHO classification. G-NEC without an adenocarcinoma component was defined as pure NEC. Results: There were six patients with mixed adeno-neuroendocrine carcinoma (MANEC), four patients with NEC, and three patients with pure NEC. TP53 was detected as the most frequent gene mutation, independent of classification (85%). RB1, ANKRD17, KMT2C, LTBP1, MAATS1, and RYR2 mutations were identified in two of three pure NEC patients but were not detected in other G-NEC patients. Gene expression analysis showed that six key transcripts of importance in NEC tumorigenesis were upregulated in two patients with pure NEC, while they were downregulated in all six MANEC patients. Conclusions: NEC and MANEC with adenocarcinoma components tend to share common pathogenic mutations, but Pure NEC has different genomic and transcriptomic characteristics than other NECs. This suggests that pure NEC has a different mechanism of tumorigenesis than other G-NECs with adenocarcinoma. This is the first study to present a comprehensive genetic analysis of G-NEC, classified by the percentage of NEC components.
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45

Saito, Kei, Yousuke Nakai, Yoshihiro Sakamoto, Kazunaga Ishigaki, Naminatsu Takahara, Junichi Arita, Takeyuki Watadani, Hiroyuki Isayama et Kazuhiko Koike. « Did neoadjuvant chemotherapy provide better long term outcomes in borderline resectable with arterial involvement (BR-A PC) ? » Journal of Clinical Oncology 36, no 4_suppl (1 février 2018) : 434. http://dx.doi.org/10.1200/jco.2018.36.4_suppl.434.

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434 Background: Recently high rates of conversion (or adjuvant) surgery were reported after neoadjuvant chemo(radiation)therapy (NAC) for borderline or locally advanced pancreatic cancer (BR/LA PC) including our phase II trial of gemcitabine, S-1 and leucovorin (GSL) combination therapy for BR PC with arterial involvement (BR-A PC) and LA PC. In our phase II trial, a high recurrence rate of 78% was noted despite a high R0 resection of 76%. Herein, we conducted a retrospective analysis of BR-A PC who underwent NAC, upfront surgery and palliative chemotherapy to evaluate the long term outcomes of NAC. Methods: Consecutive patients with BR-A PC at the University of Tokyo Hospital were retrospectively studied. Clinical outcomes in patients who underwent (NAC group) were compared with those in patients who underwent upfront surgery or palliative chemotherapy (non-NAC group). NAC was introduced in our institution from January 2014. Results: A total of 45 patients (22 non-NAC and 23 NAC group) were diagnosed with BR-A PC between January 2008 and December 2016. There were no significant differences in patient characteristics between non-NAC group and NAC group: Median age of 63 vs. 64, male in 72% vs. 52%, Performance status of 0 in 63% vs. 65%, median pretreatment CA19-9 of 175 vs. 205 U/ml. In non-NAC group, 17 underwent palliative chemotherapy as follows 8 gemcitabine alone, 3 gemcitabine and S-1 combination chemotherapy and 6 other regimens. The remaining 5 patients underwent upfront surgery with an R0 resection rate of 80%. In NAC group, a median duration of neoadjuvant chemotherapy was 4 months. A total of 14 patients underwent surgical resection with an R0 resection rate of 76%. The remaining 9 patients had disease progression during NAC and received 2nd line chemotherapy. The median follow-up time was 16.5 months in non-NAC group and 15.3 months in NAC group. The median overall survival (OS) were 19.3 vs. 21.9 months (p = 0.25). Conclusions: Both R0 resection rate and the median OS were comparable between non-NAC group and NAC group. An ideal regimen of NAC or its duration needs further investigation to prolong OS in BR-A PC.
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Binder, B., B. F. Williams, M. Eracleous, T. J. Gaetz, A. K. H. Kong, E. D. Skillman et D. R. Weisz. « THECHANDRALOCAL VOLUME SURVEY : THE X-RAY POINT-SOURCE POPULATION OF NGC 404 ». Astrophysical Journal 763, no 2 (16 janvier 2013) : 128. http://dx.doi.org/10.1088/0004-637x/763/2/128.

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Seth, Anil C., Michele Cappellari, Nadine Neumayer, Nelson Caldwell, Nate Bastian, Knut Olsen, Robert D. Blum et al. « THE NGC 404 NUCLEUS : STAR CLUSTER AND POSSIBLE INTERMEDIATE-MASS BLACK HOLE ». Astrophysical Journal 714, no 1 (14 avril 2010) : 713–31. http://dx.doi.org/10.1088/0004-637x/714/1/713.

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Chyży, K. T., M. Ehle et R. Beck. « Magnetic fields and gas in the cluster-influenced spiral galaxy NGC 4254 ». Astronomy & ; Astrophysics 474, no 2 (28 août 2007) : 415–29. http://dx.doi.org/10.1051/0004-6361:20077497.

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Chyży, K. T. « Magnetic fields and gas in the cluster-influenced spiral galaxy NGC 4254 ». Astronomy & ; Astrophysics 482, no 3 (4 mars 2008) : 755–69. http://dx.doi.org/10.1051/0004-6361:20078688.

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Richtler, T., B. Dirsch, D. Geisler, K. Gebhardt, M. Hilker, L. Infante, D. Minniti et al. « Spectroscopy of Globular Clusters in NGC 1399 - A Progress Report ». Symposium - International Astronomical Union 207 (2002) : 263–68. http://dx.doi.org/10.1017/s0074180900223838.

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We performed spectroscopy of globular clusters associated with NGC 1399 and measured radial velocities of about 450 clusters, the largest sample ever obtained for dynamical studies. In this progress report, we present the sample and the first preliminary results. Red and blue clusters have slightly different velocity dispersions in accordance with their different density profiles in the case of a spherical and isotropic model. We then measure a constant circular velocity of 422 ± 20 km/s, which agrees well with that of the inner luminous component.
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