scholarly journals Environmental processing of galaxies in H i-rich groups

2020 ◽  
Vol 500 (3) ◽  
pp. 3689-3710
Author(s):  
Robert Džudžar ◽  
Virginia Kilborn ◽  
Sarah M Sweet ◽  
Gerhardt Meurer ◽  
T H Jarrett ◽  
...  
Keyword(s):  
Atomic Hydrogen ◽  
Mass Fraction ◽  
Velocity Dispersion ◽  
Global Environment ◽  
Galaxy Mergers ◽  
Late Type ◽  
Mid Infrared ◽  
Sky Survey ◽  
Crossing Time

ABSTRACT We present and explore the resolved atomic hydrogen (H i) content of 13 H i-rich and late-type dominated groups denoted ‘Choirs’. We quantify the H i content of the Choir galaxies with respect to the median of the H i-mass fraction ($f_{\rm{{H {\small I}}}}$) of their grandparent H i Parkes All Sky Survey (HIPASS) sample. We find that the H i-mass fraction of the Choir galaxies is dispersed around the HIPASS median in the range $-1.4\le \Delta f_{\rm{{H {\small I}}}}\textrm{[dex]}\le$ 0.7, from H i-excess to H i-deficient galaxy regime. The H i-excess/H i-deficient galaxies contain more/less than 2.5 times their expected H i content with respect to the HIPASS median. We show and discuss that the environmental processing in Choirs occurs via tidal stripping and galaxy mergers. Our analysis suggests that tidal stripping contributes to the loss of the H i, while galaxy mergers contribute to the enhancement of the H i. Exploring the mid-infrared properties of Choir galaxies, we find possible environmental processing in only nine Choir galaxies, which indicates that environmental processing is more perceptible in the H i content than the mid-infrared properties. Moreover, we find that environmental processing occurs in Choir groups regardless of their global environment, whether they are in isolation or in proximity to the denser structures, such as cosmic web filaments. We explore possible scenarios of the Choirs evolution, taking into account their H i content, velocity dispersion, crossing time, and their global environment. We conclude that the most likely evolution for the majority of Choir groups is that they will become more compact as their members undergo multiple H i-rich mergers.

The Galactic Distribution and Kinematics of OH Stars (A Preliminary Discussion)

1975 ◽  
Vol 2 (6) ◽  
pp. 362-363
Author(s):  
P.F. Bowers
Keyword(s):  
Large Scale ◽  
Velocity Dispersion ◽  
Neutral Hydrogen ◽  
Late Type ◽  
Velocity Range ◽  
Hydrogen Distribution ◽  
Mira Variables ◽  
Sky Survey ◽  
Ir Stars ◽  
Galactic Distribution

The majority of OH/IR stars have been identified as M-type Mira variables, but there are a few cases where the stars have been identified as M supergiants or late-type semi-regular variables. A large number of OH sources have also been discovered with the 1612 MHz OH characteristics of OH/IR stars but no apparent optical or infrared counterparts. In several cases the velocities of these unidentified sources (OH stars) have been outside the velocity range of the neutral hydrogen distribution, suggesting that some of these sources may represent a population with a higher velocity dispersion than Population I objects (Kerr and Bowers 1974a, b). The lack of infrared and optical counterparts may indicate that the sources are quite distant, since identified OH/IR stars are often bright infrared objects. A large-scale 1612 MHz sky survey has therefore been initiated to study the galactic distribution and kinematics of the OH stars and to investigate the possibility that they may represent an older population of stars (Bowers et al. 1974).

AKARI Mid-Infrared All-sky Survey

2009 ◽  
Author(s):  
D. Ishihara ◽  
T. Onaka ◽  
H. Kataza ◽  
H. Fujiwara ◽  
S. Takita ◽  
...  
Keyword(s):  
Mid Infrared ◽  
Sky Survey

scholarly journals The AKARI/IRC mid-infrared all-sky survey

2010 ◽  
Vol 514 ◽  
pp. A1 ◽  
Author(s):  
D. Ishihara ◽  
T. Onaka ◽  
H. Kataza ◽  
A. Salama ◽  
C. Alfageme ◽  
...  
Keyword(s):  
Mid Infrared ◽  
Sky Survey

scholarly journals Physical Parameters of Late-type Contact Binaries in the Northern Catalina Sky Survey

2020 ◽  
Vol 247 (2) ◽  
pp. 50 ◽  
Author(s):  
Weijia Sun ◽  
Xiaodian Chen ◽  
Licai Deng ◽  
Richard de Grijs
Keyword(s):  
Physical Parameters ◽  
Late Type ◽  
Sky Survey ◽  
Type Contact ◽  
Contact Binaries

Optical Identification of the ROSAT All-Sky Survey Sources in Two 2° × 2° Fields

1997 ◽  
Vol 159 ◽  
pp. 427-428
Author(s):  
Y. Zhao ◽  
J. Zhong ◽  
J. Wei ◽  
J. Hu ◽  
Q. Li
Keyword(s):  
Ccd Camera ◽  
Seyfert Galaxies ◽  
Astronomical Observatory ◽  
Active Galaxies ◽  
Clusters Of Galaxies ◽  
Late Type ◽  
Optical Identification ◽  
X Ray ◽  
Sky Survey

AbstractWe used the CCD camera and spectrograph of the 2.16-m telescope of Beijing Astronomical Observatory to identify the ROSAT All-Sky survey sources in two 2° Ü 2° fields. Of a total of 16 X-ray sources, we identified 13 of them as follows: two QSOs, two Seyfert galaxies, two active galaxies, two clusters of galaxies, and five late-type stars. Three X-ray sources remained unidentified.

scholarly journals Morphology of E+A Galaxies in CL0016+16 (z=0.54)

1996 ◽  
Vol 171 ◽  
pp. 469-469
Author(s):  
Gregory Wirth ◽  
Paola Belloni
Keyword(s):  
Concentration Index ◽  
Quantitative Measure ◽  
Type Systems ◽  
Emission Lines ◽  
Galaxy Mergers ◽  
Late Type ◽  
Distant Cluster ◽  
Ram Pressure ◽  
Absorption Features

We present new results on the morphology of member galaxies in the distant cluster C10016+16 from HST images (WFCl). Based on narrow multiband ground-based photometry and spectra obtained with the Keck 10 m telescope we identify 7 new cluster members which appear to have strong Balmer absorption features but no detectable emission lines, doubling the number of such galaxies previously observed with HST in this cluster. These candidate E+A galaxies have been identified in other distant clusters, but the morphology of this population has appeared bulge-like in AC114 (Couch et al., 1994, ApJ 430, 107) and disk-like or irregular and interacting in C10939+47 and C10016+16 (Wirth et al., 1994 ApJ 435, L105). By means of the image concentration index as a quantitative measure of morphology we show that our enlarged sample of E+A objects in C10016+16 now contains some galaxies resembling bulge systems as well as the previously-identified disk-like objects. The observed heterogeneity suggests that both galaxy mergers (rapidly resulting in an r1/4 profile) and ram-pressure stripping of isolated late-type systems may originate E+A objects.

scholarly journals Environmental dependence of SFRs in late-type GAMA galaxies

2011 ◽  
Vol 7 (S284) ◽  
pp. 352-356
Author(s):  
Meiert W. Grootes ◽  
Richard J. Tuffs ◽  
Ellen Andrae ◽  
Lee S. Kelvin ◽  
Jochen Liske ◽  
...  
Keyword(s):  
Velocity Dispersion ◽  
Mass Function ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Late Type ◽  
Initial Application ◽  
Gas Consumption ◽  
Group Members ◽  
Attenuation Corrected ◽  
Environmental Dependence

AbstractPresent and past gas-fuelling of galaxies is expected to depend upon both the properties of the galaxies themselves, as well as their larger-scale environments. In the case of galaxies in groups the environment, i.e the group mass, can be probed by measuring the velocity dispersion of the group members, as done with the GAMA Galaxy Group catalogue (Robotham et al. 2011), probing the halo mass function all the way to small groups. The gas-fuelling rate of normal late-type galaxies can be traced by the SFR under the assumption of a steady state between gas-fuelling and gas-consumption by SF. We present a method to estimate disk opacities from UV/optical photometric characteristics, calibrated using the radiative transfer model of Popescu et al. (2011), applied to UV-Opt-FIR GAMA/H-ATLAS photometry for a subset of GAMA galaxies. We use the method to extract attenuation corrected SFRs for a large sample of late-type GAMA galaxies, which we use in an initial application to constrain the dependency of star formation/gas-fuelling in late-type galaxies on mass of parent DMH, and compactness of galaxy group.

scholarly journals X-ray Flare Rate of T Tauri Stars in Taurus

1995 ◽  
Vol 151 ◽  
pp. 216-217
Author(s):  
R. Neuhäuser ◽  
Th. Preibisch
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
T Tauri Stars ◽  
Medium Size ◽  
Late Type ◽  
Large Sample ◽  
X Ray ◽  
T Tauri ◽  
Sky Survey ◽  
Low Mass

AbstractWe study the X-ray emission of several hundred (young, low-mass, late-type, pre-main sequence) T Tauri stars (TTS) in the Taurus T association, a nearby well-studied region of ongoing star formation. We report on X-ray emission variability of TTS as observed with the flux-limited ROSAT All-Sky Survey (RASS). Since RASS observations are spatially unbiased, we can investigate the X-ray flare rate of TTS on a large sample. We find that large flares are very rare (once per year), while medium-size flares can occur once in ∼ 40 days.

scholarly journals Neutral Hydrogen in the Magellanic Clouds

1999 ◽  
Vol 190 ◽  
pp. 37-44
Author(s):  
L. Staveley-Smith ◽  
S. Kim ◽  
S. Stanimirović
Keyword(s):  
Atomic Hydrogen ◽  
Large Scale ◽  
Milky Way ◽  
Velocity Dispersion ◽  
Neutral Hydrogen ◽  
Distribution Functions ◽  
Magellanic Clouds ◽  
Self Gravity ◽  
Rotational Shear ◽  
Compact Array

We review observations of neutral atomic hydrogen (HI) in the Magellanic Clouds (MCs). Being the nearest gas-rich neighbours of the Milky Way the MCs give us an excellent opportunity to study in detail the structure and evolution of the interstellar medium (ISM) and the effect of interactions between galaxies. HI in emission provides a probe of the structure and velocity field of the Clouds, allowing the study of their velocity dispersion, 3-D structure, and large-scale total-mass distribution. Recent data from Australia Telescope Compact Array surveys reveal a morphology (for both Clouds) which is heavily dominated by the effects of local star-formation, rotational shear, fragmentation, self-gravity and turbulence. The new data, which has a spatial resolution down to 10 pc, also allows the study of the distribution functions in velocity and mass for HI clouds. We discuss the morphology, dynamics and giant shell population of the LMC and SMC.

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