- ID:
- ivo://CDS.VizieR/J/ApJ/679/140
- Title:
- IR measurement of quasar obscuration
- Short Name:
- J/ApJ/679/140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent work has suggested that the fraction of obscured AGNs declines with increasing luminosity, but it has been difficult to quantify this trend. Here we attempt to measure this fraction as a function of luminosity by studying the ratio of mid-infrared to intrinsic nuclear bolometric luminosity in unobscured AGNs. Because the mid-infrared is created by dust reprocessing of shorter wavelength nuclear light, this ratio is a diagnostic of f_obsc_, the fraction of solid angle around the nucleus covered by obscuring matter. In order to eliminate possible redshift dependences while also achieving a large dynamic range in luminosity, we have collected archival 24um MIPS photometry from objects with z~1 in the Sloan Digital Sky Survey DR5, the Great Observatories Origins Deep Survey, and the Cosmic Evolution Survey. To measure the bolometric luminosity for each object, we used archival optical data supplemented by GALEX data.
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- ID:
- ivo://CDS.VizieR/J/ApJ/596/748
- Title:
- IR Observations in HDF-North
- Short Name:
- J/ApJ/596/748
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The original analysis of the star formation history in the NICMOS deep images of the northern Hubble Deep Field (NHDF) is extended to the entire NHDF utilizing NICMOS and WFPC2 archival data. The roughly constant star formation rate from redshifts 16 found in this study is consistent with the original results. Star formation rates from this study, Lyman break galaxies, and submillimeter observations are now in concordance. The spike of star formation at redshift 2 due to two ultraluminous IR galaxies in the small deep NICMOS field is smoothed out in the larger area results presented here. The larger source base of this study allows comparison with predictions from hierarchical galaxy formation models. In general, the observation are consistent with the predictions. The observed luminosity functions at redshifts 16 are presented for future comparisons with theoretical galaxy evolution calculations. Mid- and far-infrared properties of the sources are also calculated and compared with observations. A candidate for the VLA source VLA 3651+1221 is discussed.
- ID:
- ivo://CDS.VizieR/J/ApJ/752/127
- Title:
- IR observations of AFGL 490
- Short Name:
- J/ApJ/752/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Spitzer IRAC and MIPS observations of the star-forming region containing intermediate-mass young stellar object (YSO) AFGL 490. We supplement these data with near-IR Two Micron All Sky Survey photometry and with deep Simultaneous Quad Infrared Imaging Device observations off the central high-extinction region. We have more than doubled the known membership of this region to 57 Class I and 303 Class II YSOs via the combined 1-24{mu}m photometric catalog derived from these data. We construct and analyze the minimum spanning tree of their projected positions, isolating one locally overdense cluster core containing 219 YSOs (60.8% of the region's members). We find this cluster core to be larger yet less dense than similarly analyzed clusters. Although the structure of this cluster core appears irregular, we demonstrate that the parsec-scale surface densities of both YSOs and gas are correlated with a power-law slope of 2.8, as found for other similarly analyzed nearby molecular clouds. We also explore the mass segregation implications of AFGL 490's offset from the center of its core, finding that it has no apparent preferential central position relative to the low-mass members.
- ID:
- ivo://CDS.VizieR/J/A+A/375/1
- Title:
- IR observations of Chandra Deep Field + HDF-South
- Short Name:
- J/A+A/375/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-IR (J and Ks) number counts and colors of galaxies detected in deep VLT-ISAAC images centered on the Chandra Deep Field (03h 32min 16s, -27{deg} 47' 25") and on the Hubble Deep Field-South. (22h 32min 55s, -60{deg} 33' 08"). The data have been obtained with the ISAAC infrared imager/spectrometer at the ESO VLT-UT1 telescope on several nights from September to December 1999 (seeing conditions around 0.7arcsec). The limiting surface brightness (1 sigma) obtained is 24.5mag/arcsec^2^ in J and 22mag/arcsec^2^ in Ks.
- ID:
- ivo://CDS.VizieR/J/AJ/142/148
- Title:
- IR observations of galaxies in the Coma cluster
- Short Name:
- J/AJ/142/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a thorough study of the specific star formation rates (sSFRs) for MIPS 24um selected galaxies in the Coma cluster. We build galaxy spectral energy distributions using optical (u', g', r', i', z'), near-infrared (J, H, Ks), and mid- to far-infrared (Infrared Array Camera and MIPS) photometry. New and archival spectra confirm 210 cluster members. Subsequently, the total infrared luminosity, galaxy stellar mass, and sSFR for the members are determined by measuring best-fit templates. Using an array of complementary diagnostics, we search for any contaminating active galactic nuclei, but find few. We compare obscured SFRs to unobscured rates derived from extinction-corrected H{alpha} emission line measurements. The agreement between these two values leads us to conclude that there is no evidence for an additionally obscured component. In our spectroscopic sample, complete to 80% for r'<19.5, we find that all starbursts are blue and are dwarfs, having masses <10^9^M_{sun}_. Examining the location of these starbursts within the cluster, we confirm that there is a lower fraction in the cluster core.
- ID:
- ivo://CDS.VizieR/J/MNRAS/386/313
- Title:
- IR observations of Mira variables
- Short Name:
- J/MNRAS/386/313
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Published data for large-amplitude asymptotic giant branch variables in the Large Magellanic Cloud (LMC) are re-analysed to establish the constants for an infrared (K) period-luminosity relation of the form MK={rho}[logP-2.38]+{delta}. A slope of {rho}=-3.51+/-0.20 and a zero-point of {delta}=-7.15+/-0.06 are found for oxygen-rich Miras (if a distance modulus of 18.39+/-0.05 is used for the LMC). Assuming this slope is applicable to Galactic Miras we discuss the zero-point for these stars using the revised Hipparcos parallaxes together with published very long baseline interferometry (VLBI) parallaxes for OH masers and Miras in globular clusters. These result in a mean zero-point of {delta}=-7.25+/-0.07 for O-rich Galactic Miras. The zero-point for Miras in the Galactic bulge is not significantly different from this value.
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/606
- Title:
- IR observations of RCW 121 (IRAS 17149-3916)
- Short Name:
- J/MNRAS/437/606
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new deep near-infrared broad- and narrow-band imaging and low-resolution spectroscopy of the star formation region RCW 121 (IRAS17149-3916) which we analyse in combination with Herschel (70, 160, 250, 350 and 500 microns) and Spitzer (3.6, 4.5, 5.8 and 8 microns) images. The near-infrared photometry reveals the presence of a stellar cluster of approximate size of 92" which is composed of at least 264 members, approximately 25 per cent of these showing excess emission at wavelengths >2.0 microns, indicative of circumstellar discs. Isochrones corresponding to ages 0.5 to 1.0Myr and A_V_=7.8 fit well the position of a large fraction of likely cluster members in the Ks versus H-Ks diagram. We find three massive star-forming cores located in the boundaries of an expanding HII region ionized by a central O-type star. From their far-infrared spectral energy distributions (SEDs) we derive masses and temperatures of the dense cores. When these young stellar objects (YSOs) have warm emission components, the 1.2 to 500 microns SEDs are fitted with Robitaille et al.'s (2006ApJS..167..256R, 2007ApJS..169..328R) star-disc-envelope model to obtain their physical parameters. The masses of the three YSOs are between 8 and 10M_{sun}_. The youngest site (core I) is undetected at wavelengths <100 microns and is at the earliest evolutionary stage that can currently be detected. The other two cores (II and III) contain YSOs of similar masses and have near-infrared counterparts, which imply a more advanced evolutionary stage. The YSO at core II has been found to have associated a jet, with strong molecular hydrogen line emission, coexisting with a water maser source. RCW 121 is another example of multiple star formation being triggered by the expansion of a single HII region.
- ID:
- ivo://CDS.VizieR/J/A+A/387/129
- Title:
- IR observations of S stars
- Short Name:
- J/A+A/387/129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric observations in the near infrared for 161 S stars, including 18 Tc-rich (intrinsic) stars, 19 Tc-deficient (extrinsic) ones and 124 candidates for Tc-deficient S stars, are presented in this paper. Based on some further investigations into the infrared properties of both Tc-rich and Tc-deficient S stars, 104 candidates are identified as very likely Tc-deficient S stars. The large number of infrared-selected Tc-deficient S stars provides a convenient way to study the physical properties and the evolutionary status of this species of S stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/649/862
- Title:
- IR phot. of IC 348 pre-main-sequence stars
- Short Name:
- J/ApJ/649/862
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 105 stellar rotation periods in the young cluster IC 348, 75 of which are new detections, increasing the total number of known periods in this cluster to 143. The period distribution resembles that seen in the heart of the Orion Nebula cluster by Herbst and colleagues. Stars estimated to be less massive than 0.25M_{sun}_ show a unimodal distribution of fast rotators (P~1-2days) and a tail of slower rotators, while stars estimated to be more massive than 0.25M_{sun}_ show a bimodal distribution with peaks at 2 and 8-days. We combine all published rotation periods in IC 348 with Spitzer mid-IR (3.6, 4.5, 5.8, and 8.0um) photometry, an unprecedentedly efficient and reliable disk indicator, in order to test the disk-braking paradigm.
- ID:
- ivo://CDS.VizieR/J/A+A/471/813
- Title:
- IR photometry around IRAS 16571-4029
- Short Name:
- J/A+A/471/813
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a near-infrared survey of the young stellar cluster associated with the IRAS 16571-4029 source. The main purpose of this survey is to study the cluster members and find the ionizing sources of the associated HII region.
