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3421. Spitzer photometry of YSC in M33
ID:
ivo://CDS.VizieR/J/A+A/534/A96
Title:
Spitzer photometry of YSC in M33
Short Name:
J/A+A/534/A96
Date:
21 Oct 2021
Publisher:
CDS
Description:
The properties of young stellar clusters (YSCs) in M33, identified from the center out to about twice the size of the bright star-forming disk, are investigated to determine possible spatial and time variations of the star formation process in this Local Group blue galaxy. 915 MIR sources have been extracted from the Spitzer 24um image. Upon inspection of H{alpha} and GALEX images and exclusion of evolved AGB stars, a sample of 648 objects is selected as candidate YSCs and their luminosity function is examined. The spectral energy distribution of each object, based on aperture photometry, is compared with Starburst99 models to derive age, mass and AV of individual clusters. In the analysis we allow for different values of the upper mass cutoff of the stellar initial mass function (IMF), the porosity of the ISM, and the dustiness of HII regions. We also examine the influence of different dust models and include corrections for incompleteness of the IMF.
3422. Spitzer point source catalogs in 7 nearby gal.
ID:
ivo://CDS.VizieR/J/ApJS/219/42
Title:
Spitzer point source catalogs in 7 nearby gal.
Short Name:
J/ApJS/219/42
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present Spitzer IRAC 3.6-8{mu}m and Multiband Imaging Photometer 24{mu}m point-source catalogs for seven galaxies: NGC6822, M33, NGC300, NGC2403, M81, NGC0247, and NGC7793. The catalogs contain a total of ~300000 sources and were created by dual-band selection of sources with >3{sigma} detections at both 3.6 and 4.5{mu}m. The source lists become significantly incomplete near m_3.6_=m_4.5~=18. We complement the 3.6 and 4.5{mu}m fluxes with 5.8, 8.0, and 24{mu}m fluxes or 3{sigma} upper limits using a combination of PSF and aperture photometry. This catalog is a resource as an archive for studying mid-infrared transients and for planning observations with the James Webb Space Telescope.
3423. Spitzer quasar and ULIRG evolution study
ID:
ivo://CDS.VizieR/J/ApJS/182/628
Title:
Spitzer quasar and ULIRG evolution study
Short Name:
J/ApJS/182/628
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the results from a comprehensive study of 74 ultraluminous infrared galaxies (ULIRGs) and 34 Palomar-Green (PG) quasars within z~0.3 observed with the Spitzer Infrared Spectrograph (IRS). The contribution of nuclear activity to the bolometric luminosity in these systems is quantified using six independent methods that span a range in wavelength and give consistent results within ~+/-10%-15% on average. This agreement suggests that deeply buried active galactic nuclei (AGNs) invisible to Spitzer IRS but bright in the far-infrared are not common in this sample. The average derived AGN contribution in ULIRGs is ~35%-40%, ranging from ~15%-35% among "cool" (f_25_/f_60_<=0.2) optically classified HII-like and LINER ULIRGs to ~50 and ~75% among warm Seyfert 2 and Seyfert 1 ULIRGs, respectively. This number exceeds ~80% in PG QSOs.
3424. Spitzer selected starbursts at z~2
ID:
ivo://CDS.VizieR/J/A+A/508/117
Title:
Spitzer selected starbursts at z~2
Short Name:
J/A+A/508/117
Date:
21 Oct 2021
Publisher:
CDS
Description:
Wide-field Spitzer surveys allow identification of thousands of potentially high-z submillimeter galaxies (SMGs) through their bright 24um emission and their mid-IR colors. We want to determine the average properties of such z~2 Spitzer-selected SMGs by combining millimeter, radio, and infrared photometry for a representative IR-flux (lambda_rest_~8um) limited sample of SMG candidates. A complete sample of 33 sources believed to be starbursts (5.8um-peakers) was selected in the (0.5deg^2^) J1046+56 field with selection criteria F_24um>400uJy, the presence of a redshifted stellar emission peak at 5.8um, and r'_Vega_>23. The field, part of the SWIRE Lockman Hole field, benefits from very deep VLA/GMRT 20cm, 50cm, and 90cm radio data (all 33 sources are detected at 50cm), and deep 160um and 70um Spitzer data. The 33 sources, with photometric redshifts ~1.5-2.5, were observed at 1.2mm with IRAM-30m/MAMBO to an rms ~0.7-0.8mJy in most cases. Their millimeter, radio, 7-band Spitzer, and near-IR properties were jointly analyzed.
3425. Spitzer sources in SWIRE/XMM/ELAIS-S1 field
ID:
ivo://CDS.VizieR/J/ApJ/703/1778
Title:
Spitzer sources in SWIRE/XMM/ELAIS-S1 field
Short Name:
J/ApJ/703/1778
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of optical spectroscopic identifications of sources detected by Spitzer at 3.6 or 24um down to ~10 and ~280uJy, respectively, in the SWIRE/XMM-Newton/ELAIS-S1 field and classified via line width analysis and diagnostic diagrams. A total of 1376 sources down to R~24.2mag have been identified (1362 detected at 3.6um, 419 at 24um, and 405 at both) by low-resolution optical spectroscopy carried out with FORS2, VIMOS, and EFOSC2 at the Very Large Telescope and 3.6m ESO telescope. The spectroscopic campaigns have been carried out over the central 0.6deg^2^ area of ELAIS-S1 which, in particular, has also been observed by XMM-Newton and Chandra. We find the first direct optical spectroscopic evidence that the fraction of active galactic nuclei (AGNs; mostly AGN2) increases with increasing F(24um)/F(R) ratio, reaching values of 70(+/-20)% in the range 316<F(24um)/F(R)<1000. We present an Infrared Array Camera-Multiband Imaging Photometer color-color diagram able to separate AGN1 from obscured AGN2 candidates. After having corrected for the spectroscopic incompleteness of our sample, the result is that the AGN fraction at F(24um)~0.8mJy is ~22(+/-7)% and decreases slowly to ~19(+/-5)% down to F(24um)~0.3mJy.
3426. Spitzer Spectra of a 10mJy galaxy sample
ID:
ivo://CDS.VizieR/J/ApJ/671/323
Title:
Spitzer Spectra of a 10mJy galaxy sample
Short Name:
J/ApJ/671/323
Date:
21 Oct 2021
Publisher:
CDS
Description:
A complete flux-limited sample of 50 galaxies is presented having f{nu}(24um)>10mJy, chosen from a survey with MIPS on Spitzer of 8.2deg^2^ in the NOAO Deep Wide-Field Survey (NDWFS) region in Bootes. Spectra obtained with the low-resolution modules of IRS on Spitzer are described for 36 galaxies in this sample; 25 show strong PAH emission features characteristic of starbursts, and 11 show silicate absorption or emission, emission lines, or featureless spectra characteristic of AGNs. Infrared or optical spectral classifications are available for 48 of the entire sample of 50; 33 galaxies are classified as starbursts and 15 as AGNs.
3427. Spitzer study of AGB stars. III.
ID:
ivo://CDS.VizieR/J/ApJ/697/1993
Title:
Spitzer study of AGB stars. III.
Short Name:
J/ApJ/697/1993
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the third and final part of a census of asymptotic giant branch (AGB) stars in Local Group dwarf irregular (dIrr) galaxies. Papers I (Jackson et al. 2007ApJ...656..818J) and II (Jackson et al. 2007ApJ...667..891J) presented the results for WLM and IC 1613. Included here are Phoenix, LGS 3, DDO 210, Leo A, Pegasus dIrr, and Sextans A. Spitzer photometry at 3.6, 4.5, 5.8, and 8um are presented, along with a more thorough treatment of background galaxy contamination than was presented in Papers I and II. We find that at least a small population of completely optically obscured AGB stars exists in each galaxy, regardless of the galaxy's metallicity, but that higher metallicity galaxies tend to harbor more stars with slight infrared excesses.
3428. Spitzer Survey of Stellar Structure in Galaxies
ID:
ivo://CDS.VizieR/J/PASP/122/1397
Title:
Spitzer Survey of Stellar Structure in Galaxies
Short Name:
J/PASP/122/1397
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Spitzer Survey of Stellar Structure in Galaxies (S^4^G) is an Exploration Science Legacy Program approved for the Spitzer post-cryogenic mission. It is a volume-, magnitude-, and size-limited (d<40Mpc, |b|>30{deg}, m_Bcorr_<15.5, and D_25_>1') survey of 2331 galaxies using the Infrared Array Camera (IRAC) at 3.6 and 4.5um. Each galaxy is observed for 240s and mapped to >=1.5D_25_. The final mosaicked images have a typical 1sigma rms noise level of 0.0072 and 0.0093MJy/sr at 3.6 and 4.5um, respectively. Our azimuthally averaged surface brightness profile typically traces isophotes at {mu}_3.6um_(AB)(1sigma)~27mag/arcsec^2^, equivalent to a stellar mass surface density of ~1M_{sun}_/pc^2^. thus provides an unprecedented data set for the study of the distribution of mass and stellar structures in the local universe. This large, unbiased, and extremely deep sample of all Hubble types from dwarfs to spirals to ellipticals will allow for detailed structural studies, not only as a function of stellar mass, but also as a function of the local environment. This article introduces the survey and describes the sample selection, the significance of the 3.6 and 4.5um bands for this study, and the data collection and survey strategies.
3429. Spitzer survey of submillimeter galaxies
ID:
ivo://CDS.VizieR/J/ApJ/699/1610
Title:
Spitzer survey of submillimeter galaxies
Short Name:
J/ApJ/699/1610
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present Spitzer-IRAC and MIPS mid-IR observations of a sample of 76 radio-detected submillimeter-selected galaxies (SMGs) with spectroscopic redshifts, the largest such sample published to date. From our data, we find that IRAC colors of SMGs are much more uniform as compared with rest-frame UV and optical colors, and z>1.5 SMGs tend to be redder in their mid-IR colors than both field galaxies and lower-z SMGs. However, the IRAC colors of the SMGs overlap those of field galaxies sufficiently that color-magnitude and color-color selection criteria suggested in the literature to identify SMG counterparts produce ambiguous counterparts within an 8" radius in 20%-35% of cases. We use a rest-frame J-H versus H-K color-color diagram and a S24/S8.0 versus S8.0/S4.5 color-color diagram to determine that 13%-19% of our sample are likely to contain active galactic nuclei which dominate their mid-IR emission.
3430. Spitzer survey of UltraVISTA deep Stripes (SMUVS)
ID:
ivo://CDS.VizieR/J/ApJS/237/39
Title:
Spitzer survey of UltraVISTA deep Stripes (SMUVS)
Short Name:
J/ApJS/237/39
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper describes new deep 3.6 and 4.5{mu}m imaging of three UltraVISTA near-infrared survey stripes within the COSMOS field. The observations were carried out with Spitzer's Infrared Array Camera (IRAC) for the Spitzer Matching Survey of the UltraVISTA Deep Stripes (SMUVS). In this work we present our data reduction techniques, and document the resulting mosaics, coverage maps, and catalogs in both IRAC passbands for the three easternmost UltraVISTA survey stripes, covering a combined area of about 0.66deg^2^, of which 0.45deg^2^ have at least 20hr of integration time. SMUVS reaches point-source sensitivities of about 25.0 AB mag (0.13{mu}Jy) at both 3.6 and 4.5{mu}m, with a significance of 4{sigma}, accounting for both survey sensitivity and source confusion. To this limit the SMUVS catalogs contain a total of ~350,000 sources, each of which is detected significantly in at least one IRAC band. Because of its uniform and high sensitivity, relatively large area coverage, and the wide array of ancillary data available in COSMOS, the SMUVS survey will be useful for a large number of cosmological investigations.