A NEW SAMPLE OF OBSCURED AGNs SELECTED FROM THE<i>XMM-NEWTON</i>AND<i>AKARI</i>SURVEYS

Terashima, Yuichi; Hirata, Yoshitaka; Awaki, Hisamitsu; Oyabu, Shinki; Gandhi, Poshak; Toba, Yoshiki; Matsuhara, Hideo

doi:10.1088/0004-637x/814/1/11

Cited by 17 publications

(15 citation statements)

References 173 publications

(86 reference statements)

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“…Two nearby galaxies, at ∼0.7 northwest and ∼2 southeast, most likely do not contribute to the IRAS flux, as they are not detected in MIR wavelengths. Terashima et al (2015), using XMM-Newton EPIC-PN data, reported the detection of a faint iron line at 6.97 keV. The Chan-dra spectrum of MCG−02−33−098 shows a slight increase at ∼7 keV, which is not significant enough to claim the presence of an excess.…”

Section: Classify 4 +4mentioning

confidence: 99%

C-Goals

Torres-Albà

Iwasawa

Díaz-Santos

et al. 2018

A&A

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We analyze Chandra X-ray observatory data for a sample of 63 luminous infrared galaxies (LIRGs), sampling the lower-infrared luminosity range of the Great Observatories All-Sky LIRG survey (GOALS), which includes the most luminous infrared selected galaxies in the local Universe. X-rays are detected for 84 individual galaxies within the 63 systems, for which arcsecond resolution X-ray images, fluxes, infrared and X-ray luminosities, spectra and radial profiles are presented. Using X-ray and mid-infrared (MIR) selection criteria, we find AGN in (31 ± 5)% of the galaxy sample, compared to the (38 ± 6)% previously found for GOALS galaxies with higher infrared luminosities (C-GOALS I). Using MIR data, we find that (59 ± 9)% of the X-ray selected AGN in the full C-GOALS sample do not contribute significantly to the bolometric luminosity of the host galaxy. Dual AGN are detected in two systems, implying a dual AGN fraction in systems that contain at least one AGN of (29 ± 14)%, compared to the (11 ± 10)% found for the C-GOALS I sample. Through analysis of radial profiles, we derive that most sources, and almost all AGN, in the sample are compact, with half of the soft X-ray emission generated within the inner ∼1 kpc. For most galaxies, the soft X-ray sizes of the sources are comparable to those of the MIR emission. We also find that the hard X-ray faintness previously reported for the bright C-GOALS I sources is also observed in the brightest LIRGs within the sample, with LFIR > 8 × 1010 L⊙.

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Section: Classify 4 +4mentioning

confidence: 99%

C-Goals

Torres-Albà

Iwasawa

Díaz-Santos

et al. 2018

A&A

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“…To confirm their nature, it would be ideal to investigate the X-ray spectra of the sample to constrain the N H , determine the unabsorbed X-ray luminosities of the sources, or look for signatures of obscured AGN such as a convex-shaped X-ray spectrum indicative of very high N H or a Fe-K emission line of high equivalent width (see e.g. Terashima et al 2015). All the sources were however either detected off-axis and/or are X-ray faint.…”

Section: X-ray Spectral Characteristicsmentioning

confidence: 99%

Identification of AGN in the XMM-Newton X-ray survey of the SMC

Maitra

Haberl

Ivanov

et al. 2019

A&A

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Context. Finding Active Galactic Nuclei (AGN) behind the Magellanic Clouds (MCs) is difficult because of the high stellar density in these fields. Although the first AGN behind the Small Magellanic Cloud (SMC) were reported in the 1980s, it is only recently that the number of AGN known behind the SMC has increased by several orders of magnitude. Aims. The mid-infrared colour selection technique has been proven to be an efficient means of identifying AGN, especially obscured sources. The X-ray regime is complementary in this regard and we use XMM-Newton observations to support the identification of AGN behind the SMC. Methods. We present a catalogue of AGN behind the SMC by correlating an updated X-ray point source catalogue from our XMM-Newton survey of the SMC with already known AGN from the literature as well as a list of candidates obtained from the ALLWISE mid-infrared colour selection criterion. We studied the properties of the sample with respect to their redshifts, luminosities and X-ray spectral characteristics. We also identified the near-infrared counterpart of the sources from the VISTA observations. Results. The redshift and luminosity distributions of the sample (where known) indicate that we detect sources from nearby Seyfert galaxies to distant and obscured quasars. The X-ray hardness ratios are compatible with those typically expected for AGN. The VISTA colours and variability are also consistent in this regard. A positive correlation was observed between the integrated X-ray flux (0.2-12 keV) and the ALLWISE and VISTA magnitudes. We further present a sample of new candidate AGN and candidates for obscured AGN. All of these make an interesting subset for further follow-up studies. An initial spectroscopic follow-up of 6 out of the 81 new candidates showed all six sources are active galaxies, albeit two with narrow emission lines.

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“…To extract the best sensitivities for most of sources, high and low Galactic latitude sky catalogs were produced by integrating all the MAXI/GSC data available then (7 months to 7 years; Hiroi et al 2011Hiroi et al , 2013Hori et al 2018). Particularly, the high latitude catalogs have been used as a basis to study extragalactic objects, mainly active galactic nuclei (AGNs; e.g., Ueda et al 2011Ueda et al , 2014Terashima et al 2015;Inoue & Tanaka 2016;Isobe et al 2016;Abeysekara et al 2017).…”

Section: Introductionmentioning

confidence: 99%

The 7-year MAXI/GSC X-Ray Source Catalog in the High Galactic Latitude Sky (3MAXI)

Kawamuro

Ueda

Shidatsu

et al. 2018

ApJS

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We present the third MAXI/GSC catalog in the high Galactic-latitude sky (|b| > 10 • ) based on the 7complementary to that in the low Galactic-latitude sky (|b| < 10 • ; Hori et al. 2018). We compile 682 sources detected at significances of s D,4−10 keV ≥ 6.5 in the 4-10 keV band. A two-dimensional image fit based on the Poisson likelihood algorithm (Cstatistics) is adopted for the detections and constraints on their fluxes and positions. The 4-10 keV sensitivity reaches ≈ 0.48 mCrab, or ≈ 5.9 × 10 −12 erg cm −2 s −1 , over the half of the survey area. Compared with the 37-month catalog (Hiroi et al. 2013), which adopted a threshold of s D,4−10 keV ≥ 7, the source number increases by a factor of ∼1.4. The fluxes in the 3-4 keV and 10-20 keV bands are further estimated, and hardness ratios (HRs) are calculated using the 3-4 keV, 4-10 keV, 3-10 keV, and 10-20 keV band fluxes. We also make the 4-10 keV lightcurves in one year bins for all the sources and characterize their variabilities with an index based on a likelihood function and the excess variance. Possible counterparts are found from five major X-ray survey catalogs by Swift , Uhuru, RXTE , XMM-Newton, and ROSAT , and an X-ray galaxy-cluster catalog (MCXC). Our catalog provides the fluxes, positions, detection significances, HRs, one-year bin lightcurves, variability indices, and counterpart candidates.

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A NEW SAMPLE OF OBSCURED AGNs SELECTED FROM THEXMM-NEWTONANDAKARISURVEYS

Cited by 17 publications

References 173 publications

C-Goals

C-Goals

Identification of AGN in the XMM-Newton X-ray survey of the SMC

The 7-year MAXI/GSC X-Ray Source Catalog in the High Galactic Latitude Sky (3MAXI)

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