- ID:
- ivo://CDS.VizieR/J/ApJ/734/13
- Title:
- GALEX ultraviolet halos around bright stars
- Short Name:
- J/ApJ/734/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have discovered ultraviolet (UV) halos extending as far as 5{deg} around four (of six) bright UV stars using data from the Galaxy Evolution Explorer satellite. These halos are due to scattering of the starlight from nearby thin, foreground dust clouds. We have placed limits of 0.58+/-0.12 and 0.72+/-0.06 on the phase function asymmetry factor (g) in the FUV (1521{AA}) and NUV (2320{AA}) bands, respectively. We suggest that these halos are a common feature around bright stars and may be used to explore the scattering function of interstellar grains at small angles.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/435/575
- Title:
- 86GHz SiO maser survey of late-type stars. III
- Short Name:
- J/A+A/435/575
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have determined extinction corrections for a sample of 441 late-type stars in the inner Galaxy, which we previously searched for SiO maser emission, using the 2MASS near-infrared photometry of the surrounding stars. From this, the near-infrared extinction law is found to be approximated by a power law A_lambda_{prop.to}lambda^-1.9+/-0.1^. Near- and mid-infrared colour-colour properties of known Mira stars are reviewed. From the distribution of the dereddened infrared colours of the SiO target stars we infer mass-loss rates between 10^-7^ and 10^-5^M_{sun}_/yr.
- ID:
- ivo://CDS.VizieR/J/A+A/619/A35
- Title:
- 86GHz SiO maser survey of late-type stars. IV
- Short Name:
- J/A+A/619/A35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an 86GHz SiO (v=1, J=2->1) maser search towards late-type stars located within |b|<0.5{deg} and 20{deg}<l<50{deg}. This search is an extension at longer longitudes of the work by Messineo et al. (2002, Cat. J/A+A/393/115). We selected 135 stars from the MSX catalog using color and flux criteria and detected 92 (86 new detections). The detection rate is 68%, the same as in our previous study. The last few decades have seen the publication of several catalogues of point sources detected in infrared surveys (MSX, 2MASS, DENIS, ISOGAL, WISE, GLIMPSE, AKARI, and MIPSGAL). We searched each catalogue for data on the 444 targets of our earlier survey and for the 135 in the survey reported here. We confirm that, as anticipated, most of our targets have colors typical of oxygen-rich AGB stars. Only one target star may have left the AGB already. Ten stars have colors typical of carbon-rich stars, meaning a contamination of our sample with carbon stars of <=1.7%.
- ID:
- ivo://CDS.VizieR/J/ApJ/778/128
- Title:
- GRB-host galaxies photometry
- Short Name:
- J/ApJ/778/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations and analysis of the host galaxies of 23 heavily dust-obscured gamma-ray bursts (GRBs) observed by the Swift satellite during the years 2005-2009, representing all GRBs with an unambiguous host-frame extinction of A_V_>1mag from this period. Deep observations with Keck, Gemini, Very Large Telescope, Hubble Space Telescope, and Spitzer successfully detect the host galaxies and establish spectroscopic or photometric redshifts for all 23 events, enabling us to provide measurements of the intrinsic host star formation rates, stellar masses, and mean extinctions. Compared to the hosts of unobscured GRBs at similar redshifts, we find that the hosts of dust-obscured GRBs are (on average) more massive by about an order of magnitude and also more rapidly star forming and dust obscured. While this demonstrates that GRBs populate all types of star-forming galaxies, including the most massive, luminous systems at z{approx}2, at redshifts below 1.5 the overall GRB population continues to show a highly significant aversion to massive galaxies and a preference for low-mass systems relative to what would be expected given a purely star-formation-rate-selected galaxy sample. This supports the notion that the GRB rate is strongly dependent on metallicity, and may suggest that the most massive galaxies in the universe underwent a transition in their chemical properties ~9Gyr ago. We also conclude that, based on the absence of unobscured GRBs in massive galaxies and the absence of obscured GRBs in low-mass galaxies, the dust distributions of the lowest-mass and the highest-mass galaxies are relatively homogeneous, while intermediate-mass galaxies (~10^9^M_{sun}_) have diverse internal properties.
- ID:
- ivo://CDS.VizieR/J/ApJS/178/247
- Title:
- H{alpha} and [NII] survey in local 11 Mpc
- Short Name:
- J/ApJS/178/247
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of a broader effort to characterize the population of star-forming galaxies in the local universe, we have carried out an H{alpha}+[NII] imaging survey for an essentially volume-limited sample of galaxies within 11Mpc of the Milky Way. This first paper describes the design of the survey, the observation, data processing, and calibration procedures, and the characteristics of the galaxy sample. The main product of the paper is a catalog of integrated H{alpha} fluxes, luminosities, and equivalent widths for the galaxies in the sample. We briefly discuss the completeness properties of the survey and compare the distribution of the sample and its star formation properties to other large H{alpha} imaging surveys. These data form the foundation for a series of follow-up studies of the star formation properties of the local volume, and the properties and duty cycles of star formation bursts in dwarf galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/677/169
- Title:
- H{alpha} galaxies at z=0.84
- Short Name:
- J/ApJ/677/169
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an H{alpha} near-infrared narrowband survey searching for star-forming galaxies at redshift z=0.84. This work is an extension of our previous narrowband studies in the optical at lower redshifts. After removal of stars and redshift interlopers (using spectroscopic and photometric redshifts), we build a complete sample of 165 H{alpha} emitters in the extended Groth strip and GOODS-N fields with L(H{alpha})>10^41^ergs/s. We compute the H{alpha} luminosity function at z=0.84 after corrections for [NII] flux contamination, extinction, systematic errors, and incompleteness. Our sources present an average dust extinction of A(H{alpha})=1.5mag. Adopting H{alpha} as a surrogate for the instantaneous SFR, we measure an extinction-corrected SFR density of 0.17^+0.03^_-0.03_M_{sun}_/yr/Mpc^3^. Combining this result to our prior measurements at z=0.02, 0.24, and 0.40, we derive an H{alpha}-based evolution of the SFR density proportional to (1+z)^{beta}^ with {beta}=3.8+/-0.5. This evolution is consistent with that derived by other authors using different SFR tracers.
- ID:
- ivo://CDS.VizieR/J/ApJS/217/5
- Title:
- HAQ survey: red QSO candidates follow-up
- Short Name:
- J/ApJS/217/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Quasi-stellar objects (QSOs) whose spectral energy distributions (SEDs) are reddened by dust either in their host galaxies or in intervening absorber galaxies are to a large degree missed by optical color selection criteria like the ones used by the Sloan Digital Sky Survey (SDSS). To overcome this bias against red QSOs, we employ a combined optical and near-infrared (near-IR) color selection. In this paper, we present a spectroscopic follow-up campaign of a sample of red candidate QSOs which were selected from the SDSS and the UKIRT Infrared Deep Sky Survey (UKIDSS). The spectroscopic data and SDSS/UKIDSS photometry are supplemented by mid-infrared photometry from the Wide-field Infrared Survey Explorer. In our sample of 159 candidates, 154 (97%) are confirmed to be QSOs. We use a statistical algorithm to identify sightlines with plausible intervening absorption systems and identify nine such cases assuming dust in the absorber similar to Large Magellanic Cloud sightlines. We find absorption systems toward 30 QSOs, 2 of which are consistent with the best-fit absorber redshift from the statistical modeling. Furthermore, we observe a broad range in SED properties of the QSOs as probed by the rest-frame 2{mu}m flux. We find QSOs with a strong excess as well as QSOs with a large deficit at rest-frame 2{mu}m relative to a QSO template. Potential solutions to these discrepancies are discussed. Overall, our study demonstrates the high efficiency of the optical/near-IR selection of red QSOs.
- ID:
- ivo://CDS.VizieR/J/A+AS/109/313
- Title:
- Heterochromatic Atmospheric Extinction
- Short Name:
- J/A+AS/109/313
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In synthetic versions of two broadband photometric systems, Johnson-Cousins and Washington, we find the dependence of atmospheric extinction corrections on colour and on macro features in the spectra of stars, such as the Balmer jump, as parameterised by Teff, logg, and [Fe/H]. We use standard passbands, a mean atmospheric extinction law measured at ESO/La Silla, extended and modified by us, and the Kurucz library of synthetic spectra. The true broadband atmospheric extinction is far more complicated than any current reduction (transformation) methods consider. Hence all broadband magnitude systems are fundamentally unphysical - they contain not the extra-atmospheric magnitudes, but unobservable magnitudes whose relation to physical magnitudes is unknown, but may differ by 0.05mag or more for hot and cool stars. Hence, it is hazardous to compare them to any synthetic magnitude system derived from either synthetic spectra or spectral scans. These problems exist to a lesser degree in intermediate band systems, but narrow band systems are relatively immune from these complexities. We do not treat either kind of system here. If our results were incorporated into a photometric reduction program, and standard stars and program stars stars carefully selected by metallicity and luminosity class, a standard magnitude system could be established that would be directly comparable to synthetic systems. As a bonus, measurements of intrinsic flux variations at the millimagnitude level would become more secure. We describe our own operational photometric transformation program that incorporates only the linear part of the dependence on colour of atmospheric extinction. Our results and prescriptions are useful for aperture photoelectric photometry, but our implementation is aimed at CCD photometry of stellar populations.
- ID:
- ivo://CDS.VizieR/J/A+AS/109/293
- Title:
- Heterochromatic extinction. I.
- Short Name:
- J/A+AS/109/293
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- 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.
