- ID:
- ivo://CDS.VizieR/J/ApJ/854/117
- Title:
- NIR stellar populations in Sextans A and Leo A
- Short Name:
- J/ApJ/854/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present JHKs observations of the metal-poor ([Fe/H]{<}-1.40) dwarf-irregular galaxies, Leo A and Sextans A, obtained with the WIYN High-resolution Infrared Camera at Kitt Peak. Their near-IR stellar populations are characterized by using a combination of color-magnitude diagrams and by identifying long-period variable stars. We detected red giant and asymptotic giant branch stars, consistent with membership of the galaxy's intermediate-age populations (2-8Gyr old). Matching our data to broadband optical and mid-IR photometry, we determine luminosities, temperatures, and dust-production rates (DPR) for each star. We identify 32 stars in LeoA and 101 stars in Sextans A with a DPR>10^-11^M_{sun}_/yr, confirming that metal-poor stars can form substantial amounts of dust. We also find tentative evidence for oxygen-rich dust formation at low metallicity, contradicting previous models that suggest oxygen-rich dust production is inhibited in metal-poor environments. The total rates of dust injection into the interstellar medium of Leo A and Sextans A are (8.2+/-1.8)x10^-9^M_{sun}_/yr and (6.2+/-0.2)x10^-7^M_{sun}/yr, respectively. The majority of this dust is produced by a few very dusty evolved stars and does not vary strongly with metallicity.
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Search Results
- ID:
- ivo://CDS.VizieR/J/other/NewA/54.30
- Title:
- NLS1s 2MASS and WISE photometry
- Short Name:
- J/other/NewA/54.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The infrared photometric study of SDSS selected Narrow Line Seyfert 1 Galaxies (NLS1s) is presented in this paper. We have made cross-identifications for such NLS1s with 2MASS and WISE observations. Finally 992 NLS1s have 2MASS and WISE counterparts. Comparisons of NLS1s with the Broad Line Seyfert 1 (BLS1s) and Seyfert 2 galaxies are made. It is shown that from 1um to 5um NLS1s are redder than BLS1s and Seyfert 2 galaxies possibly due to the richer dust environment in NLS1 nuclei or to the orientation effect while in the longer wavelengths those three kinds of sources have quite similar behavior indicative of radiation mainly from the similar warm starburst-related dust and the related AGN dust. In addition, relations between infrared colors and related (to H{beta}) strengths of some important lines are also investigated. The results show that the related strengths of [FeII] 4570{AA} are positively correlated with infrared colors in the 1-5um region, but negatively correlated with infrared colors in the 12-22um region; the related strength of [OIII] 5007{AA} are negatively correlated with infrared colors in the 1-5um region, but positively correlated with infrared colors in the 12-22um region; the related strength of [NII]6583{AA} are also negatively correlated with infrared colors in the 1-5um region, but positively correlated with infrared colors in the 12-22um region. Therefore it is indicated that the behavior of [FeII] 4570{AA} is just opposed to that for [OIII] 5007{AA} and [NII] 6583{AA} This result may be caused by different origins of such lines.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A122
- Title:
- NOEMA millimeter reduced data cubes of HerBS-89a
- Short Name:
- J/A+A/646/A122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Exploiting the sensitivity of the IRAM NOrthern Extended Millimeter Array (NOEMA) and its ability to process large instantaneous bandwidths, we have studied the morphology and other properties of the molecular gas and dust in the starburst galaxy, H-ATLAS J131611.5+281219 (HerBS- 89a), at z=2.95. High angular resolution (0.3") images reveal a partial 1.0" diameter Einstein ring in the dust continuum emission and the molecular emission lines of ^12^CO(9-8) and H_2_O(2_02_-1_11_). Together with lower angular resolution (0.6") images, we report the detection of a series of molecular lines including the three fundamental transitions of the molecular ion OH+, namely (1_1_-0_1_), (1_2_-0_1_) and (1_0_-0_1_), seen in absorption; the molecular ion CH+(1-0) seen in absorption (and tentatively in emission); two transitions of amidogen (NH_2_), namely (2_02_-1_11_) and (2_20_-2_11_) seen in emission; and HCN(1_1_-1_0_) and/or NH(1_2_-0_1_) seen in absorption. The NOEMA data are complemented with Very Large Array data tracing the ^12^CO(1-0) emission line, which provides a measurement of the total mass of molecular gas and an anchor for a CO excitation analysis. In addition, we present Hubble Space Telescope imaging that reveals the foreground lensing galaxy in the near-infrared (1.15um). Together with photometric data from the Gran Telescopio Canarias, we derive a photometric redshift of zphot=0.9^+0.3^_-0.5_ for the foreground lensing galaxy. Modelling the lensing of HerBS-89a, we reconstruct the dust continuum (magnified by a factor {mu}~=5.0) and molecular emission lines (magnified by {mu}~4-5) in the source plane, which probe scales of ~0.1" (or 800pc). The ^12^CO(9-8) and H_2_O(2_02_-1_11_) emission lines have comparable spatial and kinematic distributions; the source-plane reconstructions do not clearly distinguish between a one-component and a two-component scenario, but the latter, which reveals two compact rotating components with sizes of ~=1kpc, that are likely merging, more naturally accounts for the broad line widths observed in HerBS-89a. In the core of HerBS-89a, very dense gas with n_H2_~10^7-9^cm^-3^ is revealed by the NH_2_ emission lines and the possible HCN(1_1_-1_0_) absorption line. HerBS-89a is a powerful star forming galaxy with a molecular gas mass of M_mol_=(2.1+/-0.4)x10^11^M_{sun}_, an infrared luminosity of L_IR_=(4.6+/-0.4)x10^12^L_{sun}_, and a dust mass of M_dust_=(2.6+/-0.2)x10^9^M_{sun}_, yielding a dust-to-gas ratio {delta}_GDR_~=80. We derive a star formation rate SFR=614+/-59M_{sun}_/yr and a depletion timescale {tau}_depl_=(3.4+/-1.0)x10^8^years. The OH+ and CH+ absorption lines, which trace low (~100cm^-3^) density molecular gas, all have their main velocity component red-shifted by {DELTA}V~100km/s relative to the global CO reservoir. We argue that these absorption lines trace a rare example of gas inflow towards the center of a starburst galaxy, indicating that HerBS-89a is accreting gas from its surroundings.
794. NOIRCAT sources
- ID:
- ivo://CDS.VizieR/J/MNRAS/399/2264
- Title:
- NOIRCAT sources
- Short Name:
- J/MNRAS/399/2264
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Northern HIPASS (HI Parkes All-Sky Survey) Optical/Infrared Catalogue (NOIRCAT), an optical/near-infrared (NIR) counterpart to the Northern HIPASS Catalogue (NHICAT). Of the 1002 sources in NHICAT, 655 (66 per cent) have optical counterparts with matching optical velocities. A further 85 (8 per cent) sources have optical counterparts with matching velocities from previous radio emission-line surveys.
- ID:
- ivo://CDS.VizieR/J/MNRAS/405/2505
- Title:
- Nuclear activity in ULIRGs
- Short Name:
- J/MNRAS/405/2505
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a 5-8um spectral analysis performed on the largest sample of local ultraluminous infrared galaxies (ULIRGs) selected so far, consisting of 164 objects up to a redshift of ~0.35. The unprecedented sensitivity of the Infrared Spectrograph onboard Spitzer allowed us to develop an effective diagnostic method to quantify the active galactic nucleus (AGN) and starburst (SB) contribution to this class of objects. The large AGN over SB brightness ratio at 5-8um and the sharp difference between the spectral properties of AGN and SB galaxies in this wavelength range make it possible to detect even faint or obscured nuclear activity, and disentangle its emission from that of star formation. By defining a simple model we are also able to estimate the intrinsic bolometric corrections for both the AGN and SB components, and obtain the relative AGN/SB contribution to the total luminosity of each source.
- ID:
- ivo://CDS.VizieR/J/A+A/578/A74
- Title:
- Nuclear obscuration in LINERs
- Short Name:
- J/A+A/578/A74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Most of the optically classified low-ionisation, narrow emission-line regions (LINERs) nuclei host an active galactic nucleus (AGN). However, how they fit into the unified model (UM) of AGN is still an open question. The aims of this work are to study at mid-infrared (mid-IR) (1) the Compton-thick nature of LINERs (i.e. hydrogen column densities of N_H_>1.5x10^24^cm^-2^) and (2) the disappearance of the dusty torus in LINERs predicted from theoretical arguments. We have compiled all the available low spectral-resolution, mid-IR spectra of LINERs from the InfraRed Spectrograph (IRS) onboard Spitzer. The sample contains 40 LINERs. We have complemented the LINER sample with Spitzer/IRS spectra of PGQSOs, Type-1 Seyferts (S1s), Type-2 Seyferts (S2s), and StarBurst (SB) nuclei. We studied the AGN compared to the starburst content in our sample using different indicators: the equivalent width of the polycyclic aromatic hydrocarbon at 6.2{mu}m, the strength of the silicate feature at 9.7{mu}m, and the steepness of the mid-IR spectra. We classified the spectra as SB-dominated and AGN-dominated, according to these diagnostics and compared the average mid-IR spectra of the various classes. Moreover, we studied the correlation between the 12{mu}m luminosity, {nu}L_{nu}_(12{mu}m), and the 2-10keV energy band X-ray luminosity, L_X_(2-10keV).
- ID:
- ivo://CDS.VizieR/J/A+AS/125/419
- Title:
- Obscured AGB in Magellanic Clouds. I.
- Short Name:
- J/A+AS/125/419
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have selected 198 IRAS sources in the Large Magellanic Cloud, and 11 in the Small Magellanic Cloud, which are the best candidates to be mass-loosing AGB stars (or possibly post-AGB stars). We used the catalogues of Schwering & Israel (1990, Cat. II/181) and Reid et al. (1990, Cat. J/ApJ/348/98). They are based on the IRAS pointed observations and have lower detection limits than the Point Source Catalogue. We also made cross-identifications between IRAS sources and optical catalogues.
- ID:
- ivo://CDS.VizieR/J/ApJ/740/37
- Title:
- Obscured AGN at z~0.5-1 in the CDFS
- Short Name:
- J/ApJ/740/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify a numerically significant population of heavily obscured AGNs at z~0.5-1 in the Chandra Deep Field-South (CDF-S) and Extended Chandra Deep Field-South by selecting 242 X-ray undetected objects with infrared-based star-formation rates (SFRs) substantially higher (a factor of 3.2 or more) than their SFRs determined from the UV after correcting for dust extinction. An X-ray stacking analysis of 23 candidates in the central CDF-S region using the 4Ms Chandra data reveals a hard X-ray signal with an effective power-law photon index of {Gamma}=0.6^+0.3^_-0.4_, indicating a significant contribution from obscured AGNs. Based on Monte Carlo simulations, we conclude that 74%+/-25% of the selected galaxies host obscured AGNs, within which ~95% are heavily obscured and ~80% are Compton-thick (CT; N_H_>1.5x10^24^cm^-2^).
- ID:
- ivo://CDS.VizieR/J/ApJ/814/11
- Title:
- Obscured AGNs from XMM-Newton and AKARI
- Short Name:
- J/ApJ/814/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a new sample of obscured active galactic nuclei (AGNs) selected from the XMM-Newton serendipitous source and AKARI point-source catalogs. We match X-ray sources with infrared (18 and 90{mu}m) sources located at |b|>10{deg} to create a sample consisting of 173 objects. Their optical classifications and absorption column densities measured by X-ray spectra are compiled and study efficient selection criteria to find obscured AGNs. We apply the criteria (1) X-ray hardness ratio defined by using the 2-4.5keV and 4.5-12keV bands >-0.1 and (2) EPIC-PN count rate (CR) in the 0.2-12keV to infrared flux ratio CR/F_90_<0.1 or CR/F_18_<1 where F_18_ and F_90_ are infrared fluxes at 18 and 90{mu}m in Jy, respectively, to search for obscured AGNs. X-ray spectra of 48 candidates, for which no X-ray results have been published, are analyzed and X-ray evidence for the presence of obscured AGNs such as a convex shape X-ray spectrum indicative of absorption of N_H_~10^22-24^/cm2, a very flat continuum, or a strong Fe-K emission line with an equivalent width of >700eV is found in 26 objects. Six of them are classified as Compton-thick AGNs, and four are represented by either Compton-thin or Compton-thick spectral models. The success rate of finding obscured AGNs combining our analysis and the literature is 92% if the 18{mu}m condition is used. Of the 26 objects, 4 are optically classified as an HII nucleus and are new "elusive AGNs" in which star formation activity likely overwhelms AGN emission in the optical and infrared bands.
- ID:
- ivo://CDS.VizieR/J/A+A/556/A114
- Title:
- Obscured AGNs in XMM deep survey in CDF-S
- Short Name:
- J/A+A/556/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accretion onto supermassive black holes is believed to occur mostly in obscured active galactic nuclei (AGN). Such objects are proving rather elusive in surveys of distant galaxies, including those at X-ray energies. Our main goal is to determine whether the revised IRAC criteria of Donley et al. (2012ApJ...748..142D; objects with an infrared (IR) power-law spectral shape), are effective at selecting X-ray type-2 AGN (i.e., absorbed N_H_>10^22^cm^-2^). We present the results from the X-ray spectral analysis of 147 AGN selected by cross-correlating the highest spectral quality ultra-deep XMM-Newton and the Spitzer/IRAC catalogues in the Chandra Deep Field South. Consequently it is biased towards sources with high S/N X-ray spectra. In order to measure the amount of intrinsic absorption in these sources, we adopt a simple X-ray spectral model that includes a power-law modified by intrinsic absorption at the redshift of each source and a possible soft X-ray component.
