- ID:
- ivo://CDS.VizieR/J/ApJ/723/895
- Title:
- IR luminosities and aromatic features of 5MUSES
- Short Name:
- J/ApJ/723/895
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study a 24um selected sample of 330 galaxies observed with the infrared spectrograph for the 5mJy Unbiased Spitzer Extragalactic Survey (5MUSES). We estimate accurate total infrared luminosities by combining mid-IR spectroscopy and mid-to-far infrared photometry, and by utilizing new empirical spectral templates from Spitzer data. The infrared luminosities of this sample range mostly from 10^9^L_{sun}_ to 10^13.5^L_{sun}_, with 83% in the range 10^10^L_{sun}_<L_IR_<10^12^L_{sun}_. The redshifts range from 0.008 to 4.27, with a median of 0.144. The equivalent widths of the 6.2um aromatic feature have a bimodal distribution, probably related to selection effects. We use the 6.2um polycyclic aromatic hydrocarbon equivalent width (PAH EW) to classify our objects as starburst (SB)-dominated (44%), SB-AGN composite (22%), and active galactic nucleus (AGN)-dominated (34%). The high EW objects (SB-dominated) tend to have steeper mid-IR to far-IR spectral slopes and lower LIR and redshifts.
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- ID:
- ivo://CDS.VizieR/J/ApJ/761/184
- Title:
- IR luminosities for dusty AGNs and QSOs
- Short Name:
- J/ApJ/761/184
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mid-infrared spectroscopic measurements from the Infrared Spectrometer (IRS) on Spitzer are given for 125 hard X-ray active galactic nuclei (AGNs; 14-195keV) from the Swift Burst Alert Telescope (BAT) sample and for 32 AGNs with black hole masses (BHMs) from reverberation mapping. The 9.7{mu}m silicate feature in emission or absorption defines an infrared AGN classification describing whether AGNs are observed through dust clouds, indicating that 55% of the BAT AGNs are observed through dust. The 100 most luminous type 1 quasars as measured in {nu}L_{nu}_(7.8{mu}m) are found by comparing Sloan Digital Sky Survey (SDSS) optically discovered quasars with photometry at 22{mu}m from the Wide-Field Infrared Survey Explorer (WISE), scaled to rest frame 7.8{mu}m using an empirical template determined from IRS spectra. The most luminous SDSS/WISE quasars have the same maximum infrared luminosities for all 1.5<z<5, reaching total infrared luminosity L_IR_=10^14.4^L_{sun}_. Comparing with dust-obscured galaxies from Spitzer and WISE surveys, we find no evidence of hyperluminous obscured quasars whose maximum infrared luminosities exceed the maximum infrared luminosities of optically discovered quasars. Bolometric luminosities L_bol_ estimated from rest-frame optical or ultraviolet luminosities are compared to L_IR_. For the local AGN, the median logL_IR_/L_bol_=-0.35, consistent with a covering factor of 45% for the absorbing dust clouds. For the SDSS/WISE quasars, the median logL_IR_/L_bol_=0.1, with extremes indicating that ultraviolet-derived L_bol_ can be seriously underestimated even for type 1 quasars.
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A110
- Title:
- IR nebulae around bright massive stars
- Short Name:
- J/A+A/618/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent studies show that more than 70% of massive stars do not evolve as effectively single stars, but as members of interacting binary systems. The evolution of these stars is thus strongly altered compared to similar but isolated objects. We investigate the occurrence of parsec-scale mid-infrared nebulae around early-type stars. If they exist over a wide range of stellar properties, one possible overarching explanation is non-conservative mass transfer in binary interactions, or stellar mergers. For ~3850 stars (all OBA stars in the Bright Star Catalogue (BSC, Cat. V/50), Be stars, BeXRBs, and Be+sdO systems), we visually inspect WISE 22um images. Based on nebular shape and relative position, we distinguish five categories: offset bow shocks structurally aligned with the stellar space velocity, unaligned offset bow shocks, and centered, unresolved, and not classified nebulae. In the BSC, we find that 28%, 13%, and 0.4% of all O, B, and A stars, respectively, possess associated infrared (IR) nebulae. Additionally, 34/234 Be stars, 4/72 BeXRBs, and 3/17 Be+sdO systems are associated with IR nebulae. Aligned or unaligned bow shocks result from high relative velocities between star and interstellar medium (ISM) that are dominated by the star or the ISM, respectively. About 13% of the centered nebulae could be bow shocks seen head- or tail-on. For the rest, the data disfavor explanations as remains of parental disks, supernova remnants of a previous companion, and dust production in stellar winds. The existence of centered nebulae also at high Galactic latitudes strongly limits the global risk of coincidental alignments with condensations in the ISM. Mass loss during binary evolution seems a viable mechanism for the formation of at least some of these nebulae. In total, about 29% of the IR nebulae (2% of all OBA stars in the BSC) may find their explanation in the context of binary evolution.
- 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.