- ID:
- ivo://CDS.VizieR/J/MNRAS/449/3191
- Title:
- IR photometry of nearby RLGs
- Short Name:
- J/MNRAS/449/3191
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- By combining the data of the Two Micron All Sky Survey, the Wide-Field Infrared Survey Explorer and the AKARI satellite, we study the infrared colour properties of a sample of 2712 nearby radio-luminous galaxies (RLGs). These RLGs are divided into radio-loud (RL) active galactic nuclei (AGNs), mainly occurring at redshifts of 0.05<z<0.3 and star-forming-dominated RLGs (SFGs), mainly occurring at redshifts of 0.01<z<0.15. RL AGNs and SFGs are separately distributed in the ([3.4]-[4.6])-([4.6]-[12]) two-colour diagram, in which the RL AGNs display a double-core distribution, and the SFGs display a single-core distribution. SFGs have a redder [4.6]-[12] colour than RL AGNs due to the significant contribution from the dust component of SFGs. We find simple criteria of mid-infrared (MIR) colour separation between RL AGNs and SFGs such that: 95 per cent of RL AGNs have [4.6]-[12]<3.0 and 94 per cent of SFGs have [4.6]-[12]>3.0. We also analyse the MIR colours of RL AGNs divided into low- and high-excitation radio galaxies (LERGs and HERGs, respectively). The ([3.4]-[4.6])-([4.6]-[12]) diagram clearly shows separate distributions of LERGs and HERGs and a region of overlap, which suggests that LERGs and HERGs have different MIR properties. LERGs are responsible for the double-core distribution of RL AGNs on the ([3.4]-[4.6])-([4.6]-[12]) diagram. In addition, we also suggest 90-140{mu}m band spectral index {alpha}(90, 140)<-1.4 as a criterion of selecting nearby active galaxies with non-thermal emissions at far-infrared wavelengths.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/442/273
- Title:
- IR photometry of NGC 1893 variables
- Short Name:
- J/MNRAS/442/273
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present time series photometry of 104 variable stars in the cluster region NGC 1893. The association of the present variable candidates to the cluster NGC 1893 has been determined by using (U-B)/(B-V) and (J-H)/(H-K) two colour diagrams, and V/(V-I) colour-magnitude diagram. 45 stars are found to be main-sequence variables and these could be B-type variable stars associated with the cluster. We classified these objects as {beta} Cep, slowly pulsating B stars and new class variables as discussed by Mowlavi et al. (2013, Cat. J/A+A/554/A108). These variable candidates show ~0.005 to ~0.02mag brightness variations with periods of <1.0d. 17 new class variables are located in the H-R diagram between the slowly pulsating B stars and {delta} Scuti variables. Pulsation could be one of the causes for periodic brightness variations in these stars. The X-ray emission of present main-sequence variables associated with the cluster lies in the saturated region of X-ray luminosity versus period diagram and follows the general trend by Pizzolato et al. (2003, Cat. J/A+A/397/147).
- ID:
- ivo://CDS.VizieR/J/MNRAS/393/1408
- Title:
- IR photometry of type II quasars
- Short Name:
- J/MNRAS/393/1408
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For this paper, we collected almost all of the type II quasars so far discovered. Among them, 485 sources have photometric data at JHK bands, mainly from Two-Micron All-Sky Survey observations, 65 sources have IRAS photometric data in at least one of the three IRAS bands at 25, 60 and 100um and 15 sources have IRAS photometric data in all three IRAS bands. We find that in nearly half of all type II quasars, both the near- and far-infrared radiations are dominated by starlight or thermal reprocessing of starlight by dust in the underlying galaxy. The infrared radiation of the other group (slightly over half) is dominated by a non-thermal radiation in the near-infrared, and mostly in the far-infrared also (although there is a mixture particularly for the longer wavelengths). It is proposed that for the later group, hidden broad lines may exist in the infrared. On the basis of our and previous results, we also discuss the possibility that there are two distinct classes of type II quasars: 'true' type II quasars without a broad-line region and heavily obscured type I quasars, in full analogy with the case for type II Seyfert galaxies. No relationships can be found for either the near-infrared or the far-infrared colours and the redshift. Correlations between absolute magnitude in the near- and far-infrared with redshift are found, but could be due to a flux limit (Malmquist bias).
- ID:
- ivo://CDS.VizieR/J/AJ/126/1526
- Title:
- IR photometry of ultracool dwarfs
- Short Name:
- J/AJ/126/1526
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) observations of a sample of 134 ultracool objects (spectral types later than M7) coming from the Deep Near Infrared Survey (DENIS), Two Micron All Sky Survey (2MASS), and Sloan Digital Sky Survey (SDSS), with distances estimated to range from 7 to 105pc. Fifteen new ultracool binary candidates are reported here. Eleven known binaries are confirmed, and orbital motion is detected in some of them. We estimate that the closest binary systems in this sample have periods between 5 and 20yr, and thus dynamical masses will be derived in the near future. For the calculation of binary frequency, we restrict ourselves to systems with distances less than 20pc. After correction of the binaries bias, we find a ratio of visual binaries (at the HST limit of detection) of around 10%, and that 15% of the 26 objects within 20pc are binary systems with separations between 1 and 8AU. The observed frequency of ultracool binaries is similar to that of binaries with G-type primaries in the separation range from 2.1 to 140AU. There is also a clear deficit of ultracool binaries with separations greater than 15AU, and a possible tendency for the binaries to have mass ratios near unity. Most systems have indeed visual and near-infrared brightness ratios between 1 and 0.3. We discuss our results in the framework of current scenarios for the formation and evolution of free-floating brown dwarfs.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/122
- Title:
- IR photometry of YSO candidates toward SNR IC 443
- Short Name:
- J/ApJ/788/122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out ^12^CO, ^13^CO, and C^18^O observations toward the mixed morphology supernova remnant (SNR) IC 443. The observations cover a 1.5{deg}x1.5{deg} area and allow us to investigate the overall molecular environment of the remnant. Some northern and northeastern partial shell structure of CO gas is around the remnant. One of the partial shells, about 5' extending beyond the northeastern border of the remnant's bright radio shell, seems to just confine the faint radio halo. On the other hand, some faint CO clumps can be discerned along the eastern boundary of the faint remnant's radio halo. Connecting the eastern CO clumps, the northeastern partial shell structures, and the northern CO partial shell, we can see that a half molecular ring structure appears to surround the remnant. The LSR velocity of the half-ring structure is in the range of -5 km/s to -2 km/s, which is consistent with that of the -4 km/s molecular clouds. We suggest that the half-ring structure of the CO emission at V_LSR_~-4 km/s is associated with the SNR. The structures are possibly swept up by the stellar winds of SNR IC 443's massive progenitor. Based on the Wide-field Infrared Survey Explorer and the Two Micron All Sky Survey near-IR database, 62 young stellar object (YSO) candidates are selected within the radio halo of the remnant. These YSO candidates concentrated along the boundary of the remnant's bright radio shell are likely to be triggered by the stellar winds from the massive progenitor of SNR IC 443.
- ID:
- ivo://CDS.VizieR/J/ApJ/779/113
- Title:
- IR photometry of YSOs in the W40 region
- Short Name:
- J/ApJ/779/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multiwavelength study of the W40 star-forming region using infrared (IR) observations in the UKIRT JHK bands, Spitzer Infrared Array Camera bands, and Herschel PACS bands, 2.12{mu}m H_2_ narrowband imaging, and radio continuum observations from GMRT (610 and 1280MHz), in a field of view (FoV) of ~34'x40'. Archival Spitzer observations in conjunction with near-IR observations are used to identify 1162 Class II/III and 40 Class I sources in the FoV. The nearest-neighbor stellar surface density analysis shows that the majority of these young stellar objects (YSOs) constitute the embedded cluster centered on the high-mass source IRS 1A South. Some YSOs, predominantly the younger population, are distributed along and trace the filamentary structures at lower stellar surface density. The cluster radius is measured to be 0.44pc -- matching well with the extent of radio emission -- with a peak density of 650/pc2. The JHK data are used to map the extinction in the region, which is subsequently used to compute the cloud mass -- 126M_{sun}_ and 71M_{sun}_ for the central cluster and the northern IRS 5 region, respectively. H_2_ narrowband imaging shows significant emission, which prominently resembles fluorescent emission arising at the borders of dense regions. Radio continuum analysis shows that this region has a blister morphology, with the radio peak coinciding with a protostellar source. Free-free emission spectral energy distribution analysis is used to obtain physical parameters of the overall photoionized region and the IRS 5 sub-region.
- ID:
- ivo://CDS.VizieR/J/ApJ/624/L5
- Title:
- IR photometry of z~10 galaxies in NICMOS fields
- Short Name:
- J/ApJ/624/L5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use all available fields with deep NICMOS imaging to search for J_110_-dropouts (H_160,AB_<~28) at z~10. Our primary data set for this search is the two J_110_+H_160_ NICMOS fields taken in parallel with the Advanced Camera for Surveys (ACS) Hubble Ultra Deep Field (UDF). The 5{sigma} limiting magnitudes were ~28.6 in J_110_ and ~28.5 in H_160_ (0.6" apertures).
- ID:
- ivo://CDS.VizieR/J/ApJ/707/890
- Title:
- IR properties of E and S0 galaxies
- Short Name:
- J/ApJ/707/890
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the infrared properties of a large sample of early-type galaxies, comparing data from the Spitzer archive with Ks-band emission from the Two Micron All Sky Survey. While most representations of this data result in correlations with large scatter, we find a remarkably tight relation among colors formed by ratios of luminosities in Spitzer-Multiband Imaging Photometer bands (24, 70, and 160um) and the Ks band. Remarkably, this correlation among E and S0 galaxies follows that of nearby normal galaxies of all morphological types.
- ID:
- ivo://CDS.VizieR/J/AJ/154/201
- Title:
- IR properties of stellar bowshock nebulae
- Short Name:
- J/AJ/154/201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Arcuate infrared nebulae are ubiquitous throughout the Galactic Plane and are candidates for partial shells, bubbles, or bowshocks produced by massive runaway stars. We tabulate infrared photometry for 709 such objects using images from the Spitzer Space Telescope, the Wide-field Infrared Explorer, and the Herschel Space Observatory (HSO). Of the 709 objects identified at 24 or 22 {mu}m, 422 are detected at the HSO 70 {mu}m bandpass. Of these, only 39 are detected at HSO 160 {mu}m. The 70 {mu}m peak surface brightnesses are 0.5-2.5 Jyr/arcmin^2^. Color temperatures calculated from the 24 to 70 {mu}m ratios range from 80 to 400 K. Color temperatures from 70 to 160 {mu}m ratios are systematically lower, 40-200 K. Both of these temperature are, on average, 75% higher than the nominal temperatures derived by assuming that dust is in steady-state radiative equilibrium. This may be evidence of stellar wind bowshocks sweeping up and heating-possibly fragmenting but not destroying-interstellar dust. Infrared luminosity correlates with standoff distance, R_0_, as predicted by published hydrodynamical models. Infrared spectral energy distributions are consistent with interstellar dust exposed to either single radiant energy density, U=10^3^-10^5^ (in more than half of the objects) or a range of radiant energy densities U_min_=25 to U_max_=10^3^-10^5^ times the mean interstellar value for the remainder. Hence, the central OB stars dominate the energetics, making these enticing laboratories for testing dust models in constrained radiation environments. The spectral energy densities are consistent with polycyclic aromatic hydrocarbon fractions q_PAH_~<1% in most objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/642/673
- Title:
- IR-selected obscured AGN candidates
- Short Name:
- J/ApJ/642/673
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the large multiwavelength data set in the Chandra/SWIRE Survey (0.6deg^2^ in the Lockman Hole), we show evidence for the existence of highly obscured (Compton-thick) AGNs, estimate a lower limit to their surface density, and characterize their multiwavelength properties. Two independent selection methods based on the X-ray and infrared spectral properties are presented. The two selected samples contain (1) five X-ray sources with hard X-ray spectra and column densities >~10^24^cm^-2^ and (2) 120 infrared sources with red and AGN-dominated infrared SEDs. We estimate a surface density of at least 25 Compton-thick AGNs deg^2^ detected in the infrared in the Chandra/SWIRE field, of which 40% show distinct AGN signatures in their optical/near-infrared SEDs, the remaining being dominated by the host galaxy emission. Only ~33% of all Compton-thick AGNs are detected in the X-rays at our depth [F(0.3-8keV)>10^-15^ergs/cm^2^/s]. We report the discovery of two sources in our sample of Compton-thick AGNs, SWIRE J104409.95+585224.8 (z=2.54) and SWIRE J104406.30+583954.1 (z=2.43), which are the most luminous Compton-thick AGNs at high z currently known. The properties of these two sources are discussed in detail with an analysis of their spectra, SEDs, luminosities, and black hole masses.
