Search

Start Over Subject galaxies Rights public
1761. IRAC observations of M83 extended UV disk
ID:
ivo://CDS.VizieR/J/AJ/136/479
Title:
IRAC observations of M83 extended UV disk
Short Name:
J/AJ/136/479
Date:
21 Oct 2021
Publisher:
CDS
Description:
Spitzer Infrared Array Camera (IRAC) observations of two fields in the extended UV disk (XUV-disk) of M83 have been recently obtained, ~3R_HII_ away from the center of the galaxy (R_HII_=6.6kpc). Galaxy Evolution Explorer (GALEX) UV images have shown the two fields to host in situ recent star formation. The IRAC images are used in conjunction with GALEX data and new HI imaging from The HI Nearby Galaxy Survey (THINGS) to constrain stellar masses and ages of the UV clumps in the fields, and to relate the local recent star formation to the reservoir of available gas. Multi-wavelength photometry in the UV and mid-IR (MIR) bands of 136 UV clumps (spatial resolution >220pc) identified in the two target fields, together with model fitting of the stellar UV-MIR spectral energy distributions (SEDs), suggests that the clumps cover a range of ages between a few Myr and >1Gyr with a median value around <=100Myr, and have masses in the range 10^3^-3x10^6^M_{sun}_, with a peak ~10^4.7^M_{sun}.
1762. IRAC photometry of massive M31 globular clusters
ID:
ivo://CDS.VizieR/J/AJ/143/87
Title:
IRAC photometry of massive M31 globular clusters
Short Name:
J/AJ/143/87
Date:
21 Oct 2021
Publisher:
CDS
Description:
Several population synthesis models now predict integrated colors of simple stellar populations in the mid-infrared bands. To date, the models have not been extensively tested in this wavelength range. In a comparison of the predictions of several recent population synthesis models, the integrated colors are found to cover approximately the same range but to disagree in detail, for example, on the effects of metallicity. To test against observational data, globular clusters (GCs) are used as the closest objects to idealized groups of stars with a single age and single metallicity. Using recent mass estimates, we have compiled a sample of massive, old GCs in M31 which contain enough stars to guard against the stochastic effects of small-number statistics, and measured their integrated colors in the Spitzer/IRAC bands. Comparison of the cluster photometry in the IRAC bands with the model predictions shows that the models reproduce the cluster colors reasonably well, except for a small (not statistically significant) offset in [4.5]-[5.8]. In this color, models without circumstellar dust emission predict bluer values than are observed. Model predictions of colors formed from the V band and the IRAC 3.6 and 4.5{micro}m bands are redder than the observed data at high metallicities and we discuss several possible explanations. In agreement with model predictions, V-[3.6] and V-[4.5] colors are found to have metallicity sensitivity similar to or slightly better than V-K_s_.
1763. IRAC point sources for M32
ID:
ivo://CDS.VizieR/J/MNRAS/446/1584
Title:
IRAC point sources for M32
Short Name:
J/MNRAS/446/1584
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the population of cool, evolved stars in the Local Group dwarf elliptical galaxy M32, using Infrared Array Camera observations from the Spitzer Space Telescope. We construct deep mid-infrared colour-magnitude diagrams for the resolved stellar populations within 3.5 arcmin of M32's centre, and identify those stars that exhibit infrared excess. Our data are dominated by a population of luminous, dust-producing stars on the asymptotic giant branch (AGB) and extend to approximately 3 mag below the AGB tip. We detect for the first time a sizeable population of `extreme' AGB stars, highly enshrouded by circumstellar dust and likely completely obscured at optical wavelengths. The total dust-injection rate from the extreme AGB candidates is measured to be 7.5x10^-7^M_{sun}_/yr, corresponding to a gas mass-loss rate of 1.5x10^-4^M_{sun}_/yr. These extreme stars may be indicative of an extended star formation epoch between 0.2 and 5Gyr ago.
1764. IRAM spectra toward M33 Giant Molecular Clouds
ID:
ivo://CDS.VizieR/J/A+A/549/A17
Title:
IRAM spectra toward M33 Giant Molecular Clouds
Short Name:
J/A+A/549/A17
Date:
21 Oct 2021
Publisher:
CDS
Description:
We aim to better understand the emission of molecular tracers of the diffuse and dense gas in giant molecular clouds and the influence that metallicity, optical extinction, density, far-UV field, and star formation rate have on these tracers. Using the IRAM 30m telescope, we detected HCN, HCO^+^, ^12^CO, and ^13^CO in six GMCs along the major axis of M33 at a resolution of ~114pc and out to a radial distance of 3.4kpc. Optical, far-infrared, and submillimeter data from Herschel and other observatories complement these observations. To interpret the observed molecular line emission, we created two grids of models of photon-dominated regions, one for solar and one for M33-type subsolar metallicity. The observed HCO^+^/HCN line ratios range between 1.1 and 2.5. Similarly high ratios have been observed in the Large Magellanic Cloud. The HCN/CO ratio varies between 0.4% and 2.9% in the disk of M33. The ^12^CO/^13^CO line ratio varies between 9 and 15 similar to variations found in the diffuse gas and the centers of GMCs of the Milky Way. Stacking of all spectra allowed HNC and C_2_H to be detected. The resulting HCO^+^/HNC and HCN/HNC ratios of ~8 and 6, respectively, lie at the high end of ratios observed in a large set of (ultra-)luminous infrared galaxies. HCN abundances are lower in the subsolar metallicity PDR models, while HCO^+^ abundances are enhanced. For HCN this effect is more pronounced at low optical extinctions. The observed HCO^+^/HCN and HCN/CO line ratios are naturally explained by subsolar PDR models of low optical extinctions between 3 and 10mag and of moderate densities of n=3x10^3^-3x10^4^cm^-3^, while the FUV field strength only has a small effect on the modeled line ratios. The line ratios are almost equally well reproduced by the solar-metallicity models, indicating that variations in metallicity only play a minor role in influencing these line ratios.
1765. IR and UV star formation in ACCEPT BCGs
ID:
ivo://CDS.VizieR/J/ApJS/199/23
Title:
IR and UV star formation in ACCEPT BCGs
Short Name:
J/ApJS/199/23
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present infrared (IR) and ultraviolet (UV) photometry for a sample of brightest cluster galaxies (BCGs). The BCGs are from a heterogeneous but uniformly characterized sample, the Archive of Chandra Cluster Entropy Profile Tables (ACCEPT), of X-ray galaxy clusters from the Chandra X-ray telescope archive with published gas temperature, density, and entropy profiles. We use archival Galaxy Evolution Explorer (GALEX), Spitzer Space Telescope, and Two Micron All Sky Survey (2MASS) observations to assemble spectral energy distributions (SEDs) and colors for BCGs. We establish a mean near-UV (NUV) to 2MASS K color of 6.59+/-0.34 for quiescent BCGs. We use this mean color to quantify the UV excess associated with star formation in the active BCGs. We use both fits to a template of an evolved stellar population and library of starburst models and mid-IR star formation relations to estimate the obscured star formation rates (SFRs). We present IR and UV photometry and estimated equivalent continuous SFRs for a sample of BCGs.
1766. IRAS Bright Galaxy Survey. II
ID:
ivo://CDS.VizieR/J/AJ/110/1993
Title:
IRAS Bright Galaxy Survey. II
Short Name:
J/AJ/110/1993
Date:
21 Oct 2021
Publisher:
CDS
Description:
Complete IRAS Observations and redshifts are reported for all sources identified in the IRAS Bright Galaxy Survey - Part II (hereafter referred to as BGS2). Source positions, radial velocities, optical magnitudes, and total flux densities, peak flux densities, and spatial extents at 12, 25, and 100um are reported for 288 sources having 60um flux densities >5.24Jy, the completeness limit of the original Bright Galaxy Survey [Soifer et al. (1989AJ.....98..766S)], hereafter referred to as BGS1. These new data represent the extension of the IRAS Bright Galaxy Survey to southern declinations, Dec<~-30deg, and low Galactic latitudes, 5deg<|b|<=30deg. Although the sky coverage of the BGS2 (~19935deg^2) is 37% larger than the sky coverage of the BGS1, the number of sources is 8% smaller due primarily to large scale structure in the local distribution of galaxies. Otherwise, the sources in the BGS2 show similar relationships between number counts and flux density as observed for the 313 sources in the BGS1. The BGS2 along with the earlier BGS1, represents the best sample currently available for defining the infrared properties of galaxies in the local (z<~0.1) Universe.
1767. IRAS fluxes of UCM galaxies
ID:
ivo://CDS.VizieR/J/AJ/105/427
Title:
IRAS fluxes of UCM galaxies
Short Name:
J/AJ/105/427
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of IRAS observations of the UCM (Universidad Complutense de Madrid) sample of emission-line galaxies, which have been selected from wide-dispersion H{alpha} objective-prism plates. These data are intended to provide a convenient summary of the relevant far-infrared (FIR) properties of these galaxies. Color-color diagrams, as interpreted by theoretical models, suggest that emission from UCM galaxies is mainly due to dust heated directly by photons emitted in active star-forming regions. Statistical analysis of some samples, including the IRAS minisurvey and blue selected objective-prism samples, have been performed. Comparisons, based on FIR luminosity distributions, with the IRAS minisurvey make evident the lower metallicity of the UCM galaxies which cannot be considered as a parent population of IRAS-detected galaxies. The FIR luminosity distributions of different samples have been compared using nonparametric methods and the best correlation has been found for the UCM and Wasilewski samples. Finally, a more detailed analysis of a UCM subsample has been performed from a three component model in order to get information concerning the fractional contribution of disk, star formation activity, and nonthermal mechanisms operating in the UCM galaxies.
1768. IRAS galaxies behind southern Milky Way
ID:
ivo://CDS.VizieR/J/ApJS/89/57
Title:
IRAS galaxies behind southern Milky Way
Short Name:
J/ApJS/89/57
Date:
21 Oct 2021
Publisher:
CDS
Description:
We systematically searched for IRAS galaxies with 60nm flux density larger than 0.6Jy by using the UK Schmidt Infrared and IIIa-J Atlases in the Milky Way region (|b|<15{deg}) between l=210{deg} and 360{deg}. We first selected about 4000 IRAS point sources by using our far-infrared criteria, which are optimized for the search of IRAS galaxies behind the Milky Way region, and then inspected visually the optical counterparts of them on the Schmidt Atlas film copies. We found 966 IRAS sources associated with galaxy-like objects. The list of the objects is presented here with the IRAS source name, Galactic coordinates, IRAS flux densities, field number and emulsion of the Atlas, type and size of galaxy(-like) image, redshift, multiplicity, and cross-identification. Of these, 423 galaxies are already catalogued in the Catalog of Galaxies and Quasars Observed in the IRAS Survey (Cat. <VII/113>), and most of the remaining 543 galaxy candidates are newly identified in this search. Although the radial velocities are known for only 387 galaxies, of which 60 were newly measured by us so far, we inferred the contamination by Galactic objects to be small from the good correlation between the sky distributions of the newly identified galaxy candidates and the previously catalogued galaxies. In the regions where the Galactic molecular clouds dominate, almost all the sources were not identified as galaxies. The detected galaxies are clustered in the three regions around l=240{deg}, 280{deg}, and 315{deg}, where the projected number densities are higher than the whole-sky average of IRAS galaxies of the same flux limit.
1769. IRAS galaxies behind Taurus clouds
ID:
ivo://CDS.VizieR/J/A+A/299/347
Title:
IRAS galaxies behind Taurus clouds
Short Name:
J/A+A/299/347
Date:
21 Oct 2021
Publisher:
CDS
Description:
We carried out a complete search for IRAS galaxies in the Taurus molecular cloud region at l=169deg to 177deg and b=-19deg to -12deg. We selected a total number of 36 galaxies and galaxy candidates and looked for the 21-cm H I line in 25 objects; we detected H I emission in five of them including one with previously unknown redshift. The spatial density of IRAS galaxies with cz=4000 to 6000km/s is lower in this region than in the adjacent regions at both sides along galactic longitude, where the Perseus supercluster and the Gemini-Monoceros filament are respectively located.
1770. IRAS galaxies behind the Milky Way
ID:
ivo://CDS.VizieR/J/A+AS/104/529
Title:
IRAS galaxies behind the Milky Way
Short Name:
J/A+AS/104/529
Date:
21 Oct 2021
Publisher:
CDS
Description:
We made a search for IRAS galaxies behind the Northern Milky Way by infrared selection using IRAS Point Source Catalog and visual inspection on POSS (Palomar Observatory Sky Survey) paper prints, and carried out a redshift survey of the identified objects. This paper presents a catalog of 649 IRAS galaxies with f_60_>=0.6Jy between l=150deg and 240deg at |b|<=15deg, which contains 254 newly identified galaxies and 188 newly measured radial velocities. Due to galactic extinction, our sample is a lower limit sample of the flux limited sample of IRAS galaxies, but it can give some information on the distribution of galaxies in the region perpendicular to the Supergalactic Plane. We confirm two regions with enhanced density at l~160deg, cz~5000km/s and l~190deg, cz~5000km/s and at least two possible voids.