- ID:
- ivo://CDS.VizieR/J/ApJ/684/136
- Title:
- SEDs of ELAIS-S1 mid-IR sources
- Short Name:
- J/ApJ/684/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the broadband SEDs of the largest available highly complete (72%) spectroscopic sample of MIR-selected galaxies and AGNs at intermediate redshift. The sample contains 203 extragalactic sources from the 15um ELAIS-SWIRE survey, all with measured spectroscopic redshift. Most of these sources have full multiwavelength coverage from the FUV (GALEX) to the FIR (Spitzer) and lie in the redshift range 0.1<z<1.3. This large sample allows us for the first time to characterize the spectral properties of sources responsible for the strong evolution observed in the MIR. Based on SED-fitting, we have classified the MIR sources, identifying AGN signatures in about 50% of them. This fraction is significantly higher than that derived from optical spectroscopy (~29%) and is due in particular to the identification of AGN activity in objects spectroscopically classified as galaxies (the spectroscopic classification may be somewhat unreliable because of host galaxy dilution in the optical). It is likely that in most of our objects, the AGN is either obscured or low luminosity, and thus dominates the energetic output only in the MIR, showing up just in the range where the host galaxy SED has a minimum. The fraction of AGNs strongly depends on flux density, with that derived through the SED-fitting about 20% at S_15um_~0.5-1mJy and gradually increasing to 100% at S_15um_>10mJy, while that obtained from optical spectroscopy is never >30%, even at higher flux densities.
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- ID:
- ivo://CDS.VizieR/J/ApJ/705/14
- Title:
- Seyfert galaxies in the mid-IR
- Short Name:
- J/ApJ/705/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An analysis of archival mid-infrared (mid-IR) spectra of Seyfert galaxies from the Spitzer Space Telescope observations is presented. We characterize the nature of the mid-IR active nuclear continuum by subtracting a template starburst spectrum from the Seyfert spectra. The long wavelength part of the spectrum contains a strong contribution from the starburst-heated cool dust; this is used to effectively separate starburst-dominated Seyferts from those dominated by the active nuclear continuum. Within the latter category, the strength of the active nuclear continuum drops rapidly beyond ~20um. On average, type 2 Seyferts have weaker short-wavelength active nuclear continua as compared to type 1 Seyferts. Type 2 Seyferts can be divided into two types, those with strong polycyclic aromatic hydrocarbon (PAH) bands and those without.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/2878
- Title:
- SFR & AGN in most luminous local universe LINERs
- Short Name:
- J/MNRAS/462/2878
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This work presents the properties of 42 objects in the group of the most luminous, highest star formation rate (SFR) low-ionization nuclear emission-line regions (LINERs) at z=0.04-0.11. We obtained long-slit spectroscopy of the nuclear regions for all sources, and FIR data (Herschel and IRAS) for 13 of them. We measured emission-line intensities, extinction, stellar populations, stellar masses, ages, active galactic nuclei (AGN) luminosities, and SFRs. We find considerable differences from other low-redshift LINERs, in terms of extinction, and general similarity to star-forming galaxies. We confirm the existence of such luminous LINERs in the local universe, after being previously detected at z~0.3 by Tommasin et al. The median stellar mass of these LINERs corresponds to 6-7x10^10^M_{sun}_ which was found in previous work to correspond to the peak of relative growth rate of stellar populations and therefore for the highest SFRs. Other LINERs although showing similar AGN luminosities have lower SFR. We find that most of these sources have LAGN~LSF suggesting co-evolution of black hole and stellar mass. In general, the fraction of local LINERs on the main sequence of star-forming galaxies is related to their AGN luminosity.
- ID:
- ivo://CDS.VizieR/J/ApJ/701/1398
- Title:
- SFR for starburst galaxies
- Short Name:
- J/ApJ/701/1398
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comparison of star formation rates (SFR) determined from mid-infrared 7.7um polycyclic aromatic hydrocarbon (PAH) luminosity [SFR(PAH)], from 1.4GHz radio luminosity [SFR(radio)], and from far-ultraviolet luminosity [SFR(UV)] for a sample of 287 starburst galaxies with z<0.5 having Spitzer IRS observations.
- ID:
- ivo://CDS.VizieR/J/A+A/581/A124
- Title:
- SFR IRAS 05137+3919 star and jet multiplicity
- Short Name:
- J/A+A/581/A124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the complex high-mass star forming region IRAS05137+3919 (also known as Mol8), where multiple jets and a rich stellar cluster have been described in previous works. Our goal is to determine the number of jets and shed light on their origin, and thus determine the nature of the young stars powering these jets. We also wish to analyse the stellar clusters by resolving the brightest group of stars. The star forming region was observed in various tracers and the results were complemented with ancillary archival data. The new data represent a substantial improvement over previous studies both in resolution and frequency coverage. In particular, adaptive optics provides us with an angular resolution of 80mas in the near IR, while new mid- and far-IR data allow us to sample the peak of the spectral energy distribution and thus reliably estimate the bolometric luminosity. Thanks to the near-IR continuum and millimetre line data we can determine the structure and velocity field of the bipolar jets and outflows in this star forming region. We also find that the stars are grouped into three clusters and the jets originate in the richest of these, whose luminosity is ~2.4x10^4^L_{sun}_. Interestingly, our high-resolution near-IR images allow us to resolve one of the two brightest stars (A and B) of the cluster into a double source (A1+A2). We confirm that there are two jets and establish that they are powered by B-type stars belonging to cluster C1. On this basis and on morphological and kinematical arguments, we conclude that the less extended jet is almost perpendicular to the line of sight and that it originates in the brightest star of the cluster, while the more extended one appears to be associated with the more extincted, double source A1+A2. We propose that this is not a binary system, but a small bipolar reflection nebula at the root of the large-scale jet, outlining a still undetected circumstellar disk. The gas kinematics on a scale of ~0.2pc seems to support our hypothesis, because it appears to trace rotation about the axis of the associated jet.
- ID:
- ivo://CDS.VizieR/J/A+A/618/L10
- Title:
- SgrA* orbital motions with GRAVITY
- Short Name:
- J/A+A/618/L10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of continuous positional and polarization changes of the compact source SgrA* in high states ('flares') of its variable near- infrared emission with the near-infrared GRAVITY-Very Large Telescope Interferometer (VLTI) beam-combining instrument. In three prominent bright flares, the position centroids exhibit clockwise looped motion on the sky, on scales of typically 150 micro-arcseconds over a few tens of minutes, corresponding to about 30% the speed of light. At the same time, the flares exhibit continuous rotation of the polarization angle, with about the same 45(+/-15)-minute period as that of the centroid motions. Modelling with relativistic ray tracing shows that these findings are all consistent with a near face-on, circular orbit of a compact polarized 'hot spot' of infrared synchrotron emission at approximately six to ten times the gravitational radius of a black hole of 4 million solar masses. This corresponds to the region just outside the innermost, stable, prograde circular orbit (ISCO) of a Schwarzschild-Kerr black hole, or near the retrograde ISCO of a highly spun-up Kerr hole. The polarization signature is consistent with orbital motion in a strong poloidal magnetic field.
- ID:
- ivo://CDS.VizieR/J/ApJ/861/94
- Title:
- SHINING I. Survey observational trends
- Short Name:
- J/ApJ/861/94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Herschel/PACS spectrometer to study the global and spatially resolved far-infrared (FIR) fine-structure line emission in a sample of 52 galaxies that constitute the SHINING survey. These galaxies include star-forming, active-galactic nuclei (AGNs), and luminous infrared galaxies (LIRGs). We find an increasing number of galaxies (and kiloparsec-size regions within galaxies) with low line-to-FIR continuum ratios as a function of increasing FIR luminosity (LFIR), dust infrared color, LFIR to molecular gas mass ratio (LFIR/Mmol), and FIR surface brightness ({Sigma}FIR). The correlations between the [CII]/FIR or [OI]/FIR ratios with {Sigma}FIR are remarkably tight (~0.3dex scatter over almost four orders of magnitude in {Sigma}FIR). We observe that galaxies with L_FIR_/M_mol_>~80L_{sun}_/M_{sun}_ and {Sigma}FIR>~10^11^L_{sun}_/kpc^2^ tend to have weak fine-structure line-to-FIR continuum ratios, and that LIRGs with infrared sizes >~1kpc have line-to-FIR ratios comparable to those observed in typical star-forming galaxies. We analyze the physical mechanisms driving these trends in Paper II. The combined analysis of the [CII], [NII]122{mu}m, and [OIII]88{mu}m lines reveals that the fraction of the [CII] line emission that arises from neutral gas increases from 60% to 90% in the most active star-forming regions and that the emission originating in the ionized gas is associated with low-ionization, diffuse gas rather than with dense gas in HII regions. Finally, we report the global and spatially resolved line fluxes of the SHINING galaxies to enable the comparison and planning of future local and high-z studies.
- ID:
- ivo://CDS.VizieR/J/A+A/467/73
- Title:
- 3{sigma} hard sample of XMDS survey
- Short Name:
- J/A+A/467/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our goal is to probe the populations of obscured and unobscured AGN investigating their optical-IR and X-ray properties as a function of X-ray flux, luminosity and redshift within a hard X-ray selected sample with wide multiwavelength coverage. We selected a sample of 136 X-ray sources detected at a significance of >=3{sigma} in the 2-10keV band (F_2-10_>~10^-14^erg/cm^2^/s) in a ~1deg^2^ area in the XMM Medium Deep Survey (XMDS, Cat. <J/A+A/439/413>). The XMDS area is covered with optical photometry from the VVDS and CFHTLS surveys and infrared Spitzer data from the SWIRE survey. Based on the X-ray luminosity and X-ray to optical ratio, 132 sources are likely AGN, of which 122 have unambiguous optical - IR identification. The observed optical and IR spectral energy distributions of all identified sources are fitted with AGN/galaxy templates in order to classify them and compute photometric redshifts. X-ray spectral analysis is performed individually for sources with a sufficient number of counts and using a stacking technique for subsamples of sources at different flux levels. Hardness ratios are used to estimate X-ray absorption in individual weak sources.
- ID:
- ivo://CDS.VizieR/J/ApJ/830/14
- Title:
- SIGMA: Keck spectra of z~2 gal. in CANDELS fields
- Short Name:
- J/ApJ/830/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a survey of the internal kinematics of 49 star-forming galaxies at z~2 in the CANDELS fields with the Keck/MOSFIRE spectrograph, Survey in the near-Infrared of Galaxies with Multiple position Angles (SIGMA). Kinematics (rotation velocity V_rot_ and gas velocity dispersion {sigma}_g_) are measured from nebular emission lines which trace the hot ionized gas surrounding star-forming regions. We find that by z~2, massive star-forming galaxies (logM_*_/M_{sun}_>~10.2) have assembled primitive disks: their kinematics are dominated by rotation, they are consistent with a marginally stable disk model, and they form a Tully-Fisher relation. These massive galaxies have values of V_rot_/{sigma}_g_ that are factors of 2-5 lower than local well-ordered galaxies at similar masses. Such results are consistent with findings by other studies. We find that low-mass galaxies (logM_*_/M_{sun}_<~10.2) at this epoch are still in the early stages of disk assembly: their kinematics are often dominated by gas velocity dispersion and they fall from the Tully-Fisher relation to significantly low values of V_rot_. This "kinematic downsizing" implies that the process(es) responsible for disrupting disks at z~2 have a stronger effect and/or are more active in low-mass systems. In conclusion, we find that the period of rapid stellar mass growth at z~2 is coincident with the nascent assembly of low-mass disks and the assembly and settling of high-mass disks.
- ID:
- ivo://CDS.VizieR/J/A+A/426/97
- Title:
- SIMBA survey. 1.2-mm/IRAS sources
- Short Name:
- J/A+A/426/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a 1.2mm continuum emission survey toward 146 IRAS sources thought to harbour high-mass star forming regions. The sources have FIR colors typical of UCHII regions and were detected in the CS (2-1) line survey of Bronfman et al. (1996, Cat. J/A+AS/115/81). Regions of 15'x10', centered on each IRAS source, were mapped with an angular resolution of ~24", using the SIMBA array on the SEST telescope. 1.2mm emission was detected toward all IRAS sources. We find that the dust cores associated with these sources have typical sizes of 0.4pc and masses of 5x10^3^M_{sun}. Dust temperatures and luminosities, derived from the SED, are typically 32K and 2.3x10^5^L_{sun}_.
