- 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/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/MNRAS/464/3796
- Title:
- HI gas mass fraction estimations
- Short Name:
- J/MNRAS/464/3796
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The application of artificial neural networks (ANNs) for the estimation of HI gas mass fraction (M_HI_/M*) is investigated, based on a sample of 13 674 galaxies in the Sloan Digital Sky Survey (SDSS) with HI detections or upper limits from the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA). We show that, for an example set of fixed input parameters (g-r colour and i-band surface brightness), a multidimensional quadratic model yields M_HI_/M* scaling relations with a smaller scatter (0.22dex) than traditional linear fits (0.32dex), demonstrating that non-linear methods can lead to an improved performance over traditional approaches. A more extensive ANN analysis is performed using 15 galaxy parameters that capture variation in stellar mass, internal structure, environment and star formation. Of the 15 parameters investigated, we find that g-r colour, followed by stellar mass surface density, bulge fraction and specific star formation rate have the best connection with M_HI_/M*. By combining two control parameters, that indicate how well a given galaxy in SDSS is represented by the ALFALFA training set (PR) and the scatter in the training procedure ({sigma}_fit_), we develop a strategy for quantifying which SDSS galaxies our ANN can be adequately applied to, and the associated errors in the M_HI_/M* estimation. In contrast to previous works, our M_HI_/M* estimation has no systematic trend with galactic parameters such as M*, g-r and star formation rate. We present a catalogue of M_HI_/M* estimates for more than half a million galaxies in the SDSS, of which ~150000 galaxies have a secure selection parameter with average scatter in the M_HI_/M* estimation of 0.22dex.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A106
- Title:
- High-redshift candidate Herschel sources
- Short Name:
- J/A+A/622/A106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new catalog of high-redshift candidate Herschel sources. Our sample is obtained after applying a multifrequency filtering method (matched multifilter), which is designed to improve the signal-to-noise ratio (SNR) of faint extragalactic point sources. The method is tested against already-detected sources from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) and used to search for new high-redshift candidates. The multifilter technique produces also an estimation of the photometric redshift of the sources. When compared with a sample of sources with known spectroscopic redshift, the photometric redshift returned from the multifilter is unbiased in the redshift range 0.8<z<4.3. Using simulated data we reproduce the same unbiased result in roughly the same redshift range and determined the error (and bias above z=4) in the photometric redshifts. Based on the multifilter technique, and a selection based on color, flux, and agreement of fit between the observed photometry and assumed SED, we find 370 robust candidates to be relatively bright high-redshift sources. A second sample with 237 objects focuses on the faint end at high-redshift. These 237 sources were previously near the H-ATLAS detection limit but are now confirmed with our technique as high significance detections. Finally, we look for possible lensed Herschel sources by cross-correlating the first sample of 370 objects with two different catalogs of known low-redshift objects, the redMaPPer Galaxy Cluster Catalog and a catalog of galaxies with spectroscopic redshift from the Sloan Digital Sky Survey Data Release 14. Our search renders a number of candidates to be lensed systems from the SDSS cross-correlation but none from the redMaPPeR confirming the more likely galactic nature of the lenses.
- ID:
- ivo://CDS.VizieR/VII/182
- Title:
- High-Redshift Quasars (z>=2.2) in SGP and F401
- Short Name:
- VII/182
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (Paper I) We provide details of a multicolor ( u, b_j_, v, or, r, i), wide-field, faint magnitude survey for high-redshift (z >= 2.2 ) quasars. The survey extends over the magnitude range 16<=m_or_<=20 and covers a total area of 58.6 square degrees. Sources of incompleteness in the photometric catalog are quantified, giving the survey an effective area of 45.7 square degrees. Particular attention is paid to the details of the plate-matching and image-classification procedures used in the generation of the photometric catalog from which quasars are selected, in order that the number of spurious quasar candidates be kept to an absolute minimum. The selection of candidates incorporates a number of novel features, including treating the multicolor information as low-resolution spectra, adopting a quantitative candidate identification algorithm that employs all the available information, and requiring only that objects be detected in the or passband. We describe how model quasar spectra are used to calculate the selection function for the survey, and we present the computed sample completeness, as a function of redshift and magnitude, for a range of representative quasar types. The spectroscopic results of the survey are reported in a companion paper and the derivation of the quasar luminosity function at high redshift will be reported in a third paper. (Paper II; see also documentation files "doc.tex" or "doc.txt") In a wide-field multicolor survey (45.7 deg^2^, 16.0<=m_or_<=20.0) we have discovered 130 new quasars, of which 100 are of redshift z>=2.2. There are 49 new quasars of redshift z>=3.0 including three of z>=4.0. We provide spectra, coordinates, redshifts, broad-band magnitudes (u, b_j_, v, or, r, i), line-equivalent widths for Lyman-{alpha}/NV and CIV, FWHM CIV, and continuum spectral indices for all the new quasars. The sample includes 96 quasars selected according to the rigid criteria detailed in the companion paper by Warren, Hewett, Irwin, and Osmer. These are combined with 14 previously known quasars in one of our fields, which also meet these selection criteria, to form a complete sample. The median equivalent width for Lyman-{alpha}/NV for the complete sample is 67A, and for CIV is 31{AA}. The median FWHM CIV is 35{AA} and the median spectral index is {alpha}=-0.60. The complete sample contains at least five broad absorption-line quasars. We have obtained spectra of a total of 473 multicolor selected candidates. The proportion of quasars found, including previously known quasars, of all redshifts, is 30%. The proportion of quasars of redshift z>=2.2 in the list of candidates that satisfy the selection criteria of the complete sample is 43%. Finally we limit the sample to the 85 objects of redshift z>=2.2 in the complete sample, and summarize the relevant observational data input to the calculation of the luminosity function, comprising the redshift versus magnitude distribution and the distribution of the spectral properties. The analysis of the luminosity function will be presented in a forthcoming paper.
- ID:
- ivo://CDS.VizieR/J/A+AS/91/285
- Title:
- HII galaxies spectrophotometric catalogue
- Short Name:
- J/A+AS/91/285
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectrophotometric catalogue of 425 emission line galaxies discovered in objective prism surveys for which we derived redshifts, emission line intensities, equivalent widths, and absolute fluxes. The vast majority of objects in the catalogue are HII region-like galaxies (HII galaxies). In more than 80 HII galaxies the line [OIII]{lambda}4363 was measured with accuracy good enough to permit precise electron temperature determinations. The observational parameters that define the properties of HII galaxies as a class are characterized and discussed.
- ID:
- ivo://CDS.VizieR/J/A+A/659/A14
- Title:
- HI observations of the MATLAS dwarfs
- Short Name:
- J/A+A/659/A14
- Date:
- 25 Feb 2022 07:33:51
- Publisher:
- CDS
- Description:
- The presence of HI gas in galaxies is inextricably linked to their morphology and evolution. This paper aims to understand the HI content of the already identified 2210 dwarfs located in the low-to-moderate density environments of the MATLAS deep imaging survey. We combine the HI observations from the ATLAS3D survey, with the extragalactic HI sources from the ALFALFA survey, to extract the HI line width, velocity and mass of the MATLAS dwarfs. From the 1773 dwarfs in our sample with available HI observations, 8% (145) have an HI line detection. The majority of the dwarfs show irregular morphology, while 29% (42) are ellipticals, the largest sample of HI-bearing dwarf ellipticals (dEs) to date. Of the HI dwarf sample, 2% (3) are ultra-diffuse galaxies (UDGs), 12% have a transition-type morphology, 5% are tidal dwarf candidates, and 10% appear to be disrupted objects. In our optically selected sample, 9.5% of the dEs, 7% of the UDGs and 10% of the classical dwarfs are HI-bearing. The HI-bearing dwarfs have on average bluer colors than the dwarfs without detected HI. We find relations between the stellar and HI masses, gas fraction, color and absolute magnitude consistent with previous studies of dwarfs probing similar masses and environments. For 79% of the dwarfs identified as satellites of massive early-type galaxies, we find that the HI mass increases with the projected distance to the host. Using the HI line width, we estimate dynamical masses and find that 5% (7) of the dwarfs are dark matter deficient.
- ID:
- ivo://CDS.VizieR/VIII/73
- Title:
- HI Parkes All Sky Survey Catalogue (HIPASS)
- Short Name:
- VIII/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The HI Parkes All-Sky Survey (HIPASS) Catalogue forms the largest uniform catalogue of HI sources compiled to date, with 4315 sources identified purely by their HI content. The catalogue data comprise the southern region DE<+2{deg} of HIPASS, the first blind HI survey to cover the entire southern sky. RMS noise for this survey is 13mJy/beam and the velocity range is -1280 to 12700km/s. Data search, verification and parametrization methods are discussed along with a description of measured quantities. Full catalogue data is made available to the astronomical community including positions, velocities, velocity widths, integrated fluxes and peak flux densities. Also available are on-sky moment maps, position- velocity moment maps and spectra of catalogue sources. A number of local large-scale features are observed in the space distribution of sources including the Super-Galactic plane and the Local Void. Notably, large-scale structure is seen at low Galactic latitudes, a region normally obscured at optical wavelengths.
- ID:
- ivo://CDS.VizieR/J/MNRAS/361/34
- Title:
- HIPASS catalogue. III.
- Short Name:
- J/MNRAS/361/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the largest catalogue to date of optical counterparts for H i radio-selected galaxies, HOPCAT. Of the 4315 H i radio-detected sources from the HI Parkes All Sky Survey (HIPASS) catalogue, we find optical counterparts for 3618 (84 per cent) galaxies. Of these, 1798 (42 per cent) have confirmed optical velocities and 848 (20 per cent) are single matches without confirmed velocities. Some galaxy matches are members of galaxy groups. From these multiple galaxy matches, 714 (16 per cent) have confirmed optical velocities and a further 258 (6 per cent) galaxies are without confirmed velocities. For 481 (11 per cent), multiple galaxies are present but no single optical counterpart can be chosen and 216 (5 per cent) have no obvious optical galaxy present. Most of these "blank fields" are in crowded fields along the Galactic plane or have high extinctions. Isolated "dark galaxy" candidates are investigated using an extinction cut of A_Bj_<1mag and the blank-fields category. Of the 3692 galaxies with an A+Bj_ extinction <1mag, only 13 are also blank fields. Of these, 12 are eliminated either with follow-up Parkes observations or are in crowded fields. The remaining one has a low surface brightness optical counterpart. Hence, no isolated optically dark galaxies have been found within the limits of the HIPASS survey.
- ID:
- ivo://CDS.VizieR/I/311
- Title:
- Hipparcos, the New Reduction
- Short Name:
- I/311
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new reduction of the astrometric data as produced by the Hipparcos mission has been published, claiming accuracies for nearly all stars brighter than magnitude Hp=8 to be better, by up to a factor 4, than in the original catalogue. The new Hipparcos astrometric catalogue is checked for the quality of the data and the consistency of the formal errors as well as the possible presence of error correlations. The differences with the earlier publication are explained. Methods. The internal errors are followed through the reduction process, and the external errors are investigated on the basis of a comparison with radio observations of a small selection of stars, and the distribution of negative parallaxes. Error correlation levels are investigated and the reduction by more than a factor 10 as obtained in the new catalogue is explained. Results. The formal errors on the parallaxes for the new catalogue are confirmed. The presence of a small amount of additional noise, though unlikely, cannot be ruled out. Conclusions. The new reduction of the Hipparcos astrometric data provides an improvement by a factor 2.2 in the total weight compared to the catalogue published in 1997, and provides much improved data for a wide range of studies on stellar luminosities and local galactic kinematics.
