Search

Start Over Subject photometry
2981. IRAC identifications for 510 AEGIS20 radio sources
ID:
ivo://CDS.VizieR/J/ApJ/756/72
Title:
IRAC identifications for 510 AEGIS20 radio sources
Short Name:
J/ApJ/756/72
Date:
21 Oct 2021
Publisher:
CDS
Description:
Infrared 3.6-8{mu}m images of the Extended Groth Strip yield plausible counterpart identifications for all but one of 510 radio sources in the AEGIS20 S(1.4GHz)>50{mu}Jy sample. This is the first such deep sample that has been effectively 100% identified. Achieving the same identification rate at R band would require observations reaching R_AB_>27. Spectroscopic redshifts are available for 46% of the sample and photometric redshifts for an additional 47%. Almost all of the sources with 3.6{mu}m AB magnitudes brighter than 19 have spectroscopic redshifts z<1.1, while fainter objects predominantly have photometric redshifts with 1<~z<~3. Unlike more powerful radio sources that are hosted by galaxies having large stellar masses within a relatively narrow range, the AEGIS20 counterparts have stellar masses spanning more than a factor of 10 at z~1. The sources are roughly 10%-15% starbursts at z<~0.5 and 20%-25% active galactic nuclei mostly at z>1 with the remainder of uncertain nature.
2982. IRAC/MIPS photometry in Cha I
ID:
ivo://CDS.VizieR/J/ApJ/675/1375
Title:
IRAC/MIPS photometry in Cha I
Short Name:
J/ApJ/675/1375
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a census of circumstellar disks in the Chamaeleon I star-forming region. Using the Infrared Array Camera and the Multiband Imaging Photometer on board the Spitzer Space Telescope, we have obtained images of Chamaeleon I at 3.6, 4.5, 5.8, 8.0, and 24um. To search for new disk-bearing members of the cluster, we have performed spectroscopy on objects that have red colors in these data. Through this work, we have discovered four new members of Chamaeleon I with spectral types of M4, M6, M7.5, and L0.
2983. IRAC/MUSYC SIMPLE survey
ID:
ivo://CDS.VizieR/J/ApJ/727/1
Title:
IRAC/MUSYC SIMPLE survey
Short Name:
J/ApJ/727/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the Spitzer IRAC/MUSYC Public Legacy Survey in the Extended CDF-South (SIMPLE), which consists of deep IRAC observations covering the ~1600arcmin^2^ area surrounding GOODS-S. The limiting magnitudes of the SIMPLE IRAC mosaics typically are 23.8, 23.6, 21.9, and 21.7, at 3.6um, 4.5um, 5.8um, and 8.0um, respectively (5{sigma} total point source magnitudes in AB). The SIMPLE IRAC images are combined with the 10'x15' GOODS IRAC mosaics in the center. We give detailed descriptions of the observations, data reduction, and properties of the final images, as well as the detection and photometry methods used to build a catalog. Using published optical and near-infrared data from the Multiwavelength Survey by Yale-Chile (MUSYC), we construct an IRAC-selected catalog, containing photometry in UBVRIz'JHK, [3.6um], [4.5um], [5.8um], and [8.0um]. The catalog contains 43,782 sources with S/N>5 at 3.6um, 19,993 of which have 13-band photometry. We compare this catalog to the publicly available MUSYC and FIREWORKS catalogs and discuss the differences. Using a high signal-to-noise sub-sample of 3391 sources with ([3.6]+[4.5])/2<21.2, we investigate the star formation rate history of massive galaxies out to z~1.8. We find that at z~1.8 at least 30+/-7% of the most massive galaxies (M*>10^11^M_{sun}_) are passively evolving, in agreement with earlier results from surveys covering less area.
2984. IRAC observations of IC 1795
ID:
ivo://CDS.VizieR/J/ApJ/733/113
Title:
IRAC observations of IC 1795
Short Name:
J/ApJ/733/113
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a deep Spitzer/Infrared Array Camera (IRAC) survey of the OB association IC 1795 carried out to investigate the evolution of protoplanetary disks in regions of massive star formation. Combining Spitzer/IRAC data with Chandra/Advanced CCD Imaging Spectrometer observations, we find 289 cluster members. An additional 340 sources with an infrared excess, but without X-ray counterpart, are classified as cluster member candidates. Both surveys are complete down to stellar masses of about 1M_{sun}_. We present pre-main-sequence isochrones computed for the first time in the Spitzer/IRAC colors. The age of the cluster, determined via the location of the Class III sources in the [3.6]-[4.5]/[3.6] color-magnitude diagram, is in the range of 3-5Myr. As theoretically expected, we do not find any systematic variation in the spatial distribution of disks within 0.6pc of either O-type star in the association. However, the disk fraction in IC 1795 does depend on the stellar mass: sources with masses >2M_{sun}_ have a disk fraction of ~20%, while lower mass objects (2-0.8M_{sun}_) have a disk fraction of ~50%. This implies that disks around massive stars have a shorter dissipation timescale.
2985. 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}.
2986. IRAC photometry of M8
ID:
ivo://CDS.VizieR/J/MNRAS/407/1170
Title:
IRAC photometry of M8
Short Name:
J/MNRAS/407/1170
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present photometry and images (3.6, 4.5, 5.8 and 8.0um) from the Spitzer Infrared Array Camera (IRAC) of the star-forming region Messier 8 (M8). The IRAC photometry reveals ongoing star formation in the M8 complex, with 64 class 0/I and 168 class II sources identified in several locations in the vicinity of submm gas cores/clumps.
2987. 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_.
2988. IRAC point-source catalog of Vela-D cloud
ID:
ivo://CDS.VizieR/J/ApJ/719/9
Title:
IRAC point-source catalog of Vela-D cloud
Short Name:
J/ApJ/719/9
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper presents the observations of Cloud D in the Vela Molecular Ridge, obtained with the Infrared Array Camera (IRAC) camera on board the Spitzer Space Telescope at the wavelengths {lambda}=3.6, 4.5, 5.8, and 8.0um. A photometric catalog of point sources, covering a field of approximately 1.2deg^2^, has been extracted and complemented with additional available observational data in the millimeter region. Previous observations of the same region, obtained with the Spitzer MIPS camera in the photometric bands at 24um and 70um, have also been reconsidered to allow an estimate of the spectral slope of the sources in a wider spectral range. A total of 170299 point sources, detected at the 5{sigma} sensitivity level in at least one of the IRAC bands, have been reported in the catalog. There were 8796 sources for which good quality photometry was obtained in all four IRAC bands. For this sample, a preliminary characterization of the young stellar population based on the determination of spectral slope is discussed; combining this with diagnostics in the color-magnitude and color-color diagrams, the relative population of young stellar objects (YSOs) in different evolutionary classes has been estimated and a total of 637 candidate YSOs have been selected.
2989. 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.
2990. IR and Optical Photometry of galaxies
ID:
ivo://CDS.VizieR/J/A+AS/100/583
Title:
IR and Optical Photometry of galaxies
Short Name:
J/A+AS/100/583
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)