- ID:
- ivo://CDS.VizieR/J/A+A/574/A126
- Title:
- HeViCS. XVIII. Star-forming dwarf galaxies
- Short Name:
- J/A+A/574/A126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To assess the effects of the cluster environment on the different components of the interstellar medium, we analyse the far-infrared (FIR) and submillimetre (submm) properties of a sample of star-forming dwarf galaxies detected by the Herschel Virgo Cluster Survey (HeViCS). We determine dust masses and dust temperatures by fitting a modified black body function to the spectral energy distributions (SEDs). Stellar and gas masses, star formation rates (SFRs), and metallicities are obtained from the analysis of a set of ancillary data. Dust is detected in 49 out of a total 140 optically identified dwarfs covered by the HeViCS field; considering only dwarfs brighter than m_B_=18mag, this gives a detection rate of 43%. After evaluating different emissivity indices, we find that the FIR-submm SEDs are best-fit by {beta}=1.5, with a median dust temperature T_d_=22.4K. Assuming {beta}=1.5, 67% of the 23 galaxies detected in all five Herschel bands show emission at 500{mu}m in excess of the modified black-body model. The fraction of galaxies with a submillimetre excess decreases for lower values of {beta}, while a similarly high fraction (54%) is found if a {beta}-free SED modelling is applied. The excess is inversely correlated with SFR and stellar masses. To study the variations in the global properties of our sample that come from environmental effects, we compare the Virgo dwarfs to other Herschel surveys, such as the Key Insights into Nearby Galaxies: Far-Infrared Survey with Herschel (KINGFISH), the Dwarf Galaxy Survey (DGS), and the HeViCS Bright Galaxy Catalogue (BGC). We explore the relations between stellar mass and HI fraction, specific star formation rate, dust fraction, gas-to-dust ratio over a wide range of stellar masses (from 10^7^ to 10^11^M_{sun}_) for both dwarfs and spirals. Highly HI-deficient Virgo dwarf galaxies are mostly characterised by quenched star formation activity and lower dust fractions giving hints for dust stripping in cluster dwarfs. However, to explain the large dust-to-gas mass ratios observed in these systems, we find that the fraction of dust removed has to be less than that of the HI component. The cluster environment seems to mostly affect the gas component and star formation activity of the dwarfs. Since the Virgo star-forming dwarfs are likely to be crossing the cluster for the first time, a longer timescale might be necessary to strip the more centrally concentrated dust distribution.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/394/1857
- Title:
- H_2_/HI ratio in galaxies
- Short Name:
- J/MNRAS/394/1857
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We revisit the mass ratio {eta}_galaxy_ between molecular hydrogen (H2) and atomic hydrogen (HI) in different galaxies from a phenomenological and theoretical viewpoint.
- ID:
- ivo://CDS.VizieR/J/MNRAS/440/696
- Title:
- HI absorption in nearby radio galaxies
- Short Name:
- J/MNRAS/440/696
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using archival data from the Hi Parkes All-Sky Survey (HIPASS), we have searched for 21cm line absorption in 204 nearby radio and star-forming galaxies with continuum flux densities greater than S_1.4_~250mJy within the redshift range 0<cz<12000km/s. By applying a detection method based on Bayesian model comparison, we successfully detect and model absorption against the radio-loud nuclei of four galaxies, of which the Seyfert 2 galaxy 2MASX J130804201-2422581 was previously unknown. All four detections were achieved against compact radio sources, which include three active galactic nuclei (AGNs) and a nuclear starburst, exhibiting high dust and molecular gas content. Our results are consistent with the detection rate achieved by the recent ALFALFA (Arecibo Legacy Fast Arecibo L-band Feed Array) Hi absorption pilot survey by Darling et al. and we predict that the full ALFALFA survey should yield more than three to four times as many detections as we have achieved here. Furthermore, we predict that future all-sky surveys on the Square Kilometre Array precursor telescopes will be able to detect such strong absorption systems associated with type 2 AGNs at much higher redshifts, providing potential targets for detection of H_2_O megamaser emission at cosmological redshifts.
- ID:
- ivo://CDS.VizieR/J/ApJ/871/17
- Title:
- HI and CO observations of M33 interstellar medium
- Short Name:
- J/ApJ/871/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We utilize the multi-wavelength data of M33 to study the origin of turbulence in its interstellar medium. We find that the HI turbulent energy surface density inside 8kpc is ~1-3x10^46^erg/pc^2^, and has no strong dependence on galactocentric radius because of the lack of variation in HI surface density and HI velocity dispersion. Then, we consider the energies injected by supernovae (SNe), the magneto-rotational instability (MRI), and the gravity-driven turbulence from accreted materials as the sources of turbulent energy. For a constant dissipation time of turbulence, the SNe energy can maintain turbulence inside ~4kpc radius (equivalent to ~0.5R_25_), while the MRI energy is always smaller than the turbulent energy within 8kpc radius. However, when we let the dissipation time to be equal to the crossing time of turbulence across the HI scale height, the SNe energy is enough to maintain turbulence out to 7kpc radius, and the sum of SNe and MRI energies is able to maintain turbulence out to 8kpc radius. Due to lack of constraint in the mass accretion rate through the disk of M33, we cannot rule out the accretion driven turbulence as a possible source of energy. Furthermore, by resolving individual giant molecular clouds in M33, we also show that the SNe energy can maintain turbulence within individual molecular clouds with ~1% of coupling efficiency. This result strengthens the proposition that stellar feedback is an important source of energy to maintain turbulence in nearby galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/182/378
- Title:
- HI and OVI absorbers in nearby Universe
- Short Name:
- J/ApJS/182/378
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze intergalactic HI and OVI absorbers with {nu}<5000km/s in Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer spectra of 76 active galactic nuclei. The baryons traced by HI/OVI absorption are clearly associated with the extended surroundings of galaxies; for impact parameters <400kpc they are 2-4 times more numerous as those inside the galaxies. This large reservoir of matter likely plays a major role in galaxy evolution. We tabulate the fraction of absorbers having a galaxy of a given luminosity within a given impact parameter ({rho}) and velocity difference ({Delta}v), as well as the fraction of galaxies with an absorber closer than a given {rho} and {Delta}v. We identify possible "void absorbers" ({rho}>3Mpc to the nearest L_*_ galaxy), although at v<2500km/s all absorbers are within 1.5Mpc of an L>0.1L_*_ galaxy. The absorber properties depend on {rho}, but the relations are not simple correlations.
- ID:
- ivo://CDS.VizieR/J/ApJ/842/133
- Title:
- HI-bearing ultra-diffuse ALFALFA galaxies
- Short Name:
- J/ApJ/842/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 115 very low optical surface brightness, highly extended, HI-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently discovered "ultra-diffuse" galaxies (UDGs). However, these systems are bluer and have more irregular morphologies than other UDGs, are isolated, and contain significant reservoirs of HI. We find that while these sources have normal star formation rates for HI-selected galaxies of similar stellar mass, they have very low star formation efficiencies. We further present deep optical and HI-synthesis follow-up imaging of three of these HI-bearing ultra-diffuse sources. We measure HI diameters extending to ~40kpc, but note that while all three sources have large HI diameters for their stellar mass, they are consistent with the HI mass-HI radius relation. We further analyze the HI velocity widths and rotation velocities for the unresolved and resolved sources, respectively, and find that the sources appear to inhabit halos of dwarf galaxies. We estimate spin parameters, and suggest that these sources may exist in high spin parameter halos, and as such may be potential HI-rich progenitors to the ultra-diffuse galaxies observed in cluster environments.
- ID:
- ivo://CDS.VizieR/J/A+A/428/823
- Title:
- HI catalog of low surface brightness galaxies
- Short Name:
- J/A+A/428/823
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using both the Arecibo 305m and the Nancay decimetric 100-m class radio telescopes, we have observed the H I line of 116 Low Surface Brightness (LSB) galaxies from the Bothun et al. (1985AJ.....90.2487B) subset of LSB galaxies in the Uppsala General Catalog. Combining our results with previous studies done on the Bothun et al. (1985AJ.....90.2487B) catalog results in a well-defined catalog of H I properties of 526 LSB galaxies ranging in redshift space from 0<=z<=0.1. With this catalog in hand, we have been able to explore the parameter space occupied by LSB galaxies more completely than has been previously possible.
- ID:
- ivo://CDS.VizieR/VII/85A
- Title:
- Hickson Compact Groups of Galaxies
- Short Name:
- VII/85A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog is a list of 100 compact groups of galaxies identified by a systematic search of the Palomar Observatory Sky Survey red prints. Each group contains four or more galaxies, has an estimated mean surface brightness brighter than 26.0 magnitude per arcsec and satisfies an isolation criterion. The catalog includes running numbers, equatorial coordinates, group types according to the two brightest members, number of galaxies in the group, angular diameters of the smallest circles containing the geometric centers of all group members, total magnitudes (red) of those galaxies counted as group members, estimated red magnitudes of the brightest galaxies in the groups, corrected redshifts of the brightest galaxies, and other designations of the groups.
- ID:
- ivo://CDS.VizieR/J/A+AS/117/39
- Title:
- Hickson Compact Groups of Galaxies I.
- Short Name:
- J/A+AS/117/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Far Infrared (FIR) properties of galaxies which are members of compact groups bear relevant information on the dynamical status and the physical properties of these structures. All studies published so far have been undermined by the poor sensitivity and spatial resolution of the IRAS-PSC and IRAS Sky Survey data. We used the HIRAS software available at the IRAS server at the Laboratory for Space Research in Groningen to fully exploit the redundancy of the IRAS data and to approach the theoretical diffraction limit of IRAS. Among the 97 groups which were observed by IRAS, 62 were detected in at least one band, while reliable upper limits were derived for all the others. Among the detected groups, 49 were fully or partially resolved, i.e. it was possible to discriminate which member or members emit most of the FIR light. At 60{mu}m, for instance, 87 individual sources were detected in 62 groups. In order to ease the comparison with data obtained at other wavelengths - and in particular in the X and radio domains - we give co-added and HIRAS maps for all the detected groups.
- ID:
- ivo://CDS.VizieR/VII/213
- Title:
- Hickson's Compact groups of Galaxies
- Short Name:
- VII/213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog of groups (file "groups.dat") is a list of 100 compact groups of galaxies identified by a systematic search of the Palomar Observatory Sky Survey red prints. Each group contains four or more galaxies, has an estimated mean surface brightness brighter than 26.0 magnitude per arcsec^2^ and satisfies an isolation criterion. Dynamical parameters were derived for 92 of the 100 groups, which are listed in file "dynamics.dat"; the Hubble constant was assumed to be Ho=100km/s/Mpc. Data about individual galaxies in these groups are merged into the "galaxies.dat" file; these data include photometric parameters, morphology, redshifts and absolute magnitudes originally published in four different papers. They result from CCD observations at CFHT (Canada-France-Hawaii Telescope) in 1983-1985. Redshifts were observed at the 1.5m telescope of the F.L. Whipple Observatory on Mt. Hopkins, Arizona, over the period 1984-1986, in wavelength range 470-710nm; the remaining fainter galaxies were observed with the CFHT.
