2007A&A...468..129T


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.19CEST00:40:23

2007A&A...468..129T - Astronomy and Astrophysics, volume 468, 129-137 (2007/6-2)

Searching for hidden AGN in nearby star-forming galaxies with Chandra.

TZANAVARIS P. and GEORGANTOPOULOS I.

Abstract (from CDS):

We searched for X-ray signatures of AGN in a sample of star-forming, relatively early-type, nearby spiral galaxies, from the optical spectroscopic sample of Ho et al. The tight correlations between the masses of central supermassive black holes and bulge mass or velocity dispersion suggest that such galaxies are likely to host black holes in their centres. The aim is to look for X-ray signs of activity in these gas-rich environments. We identified Chandra ACIS-S images of the X-ray counterparts of 9 sources from the optical sample. We isolated 10 individual X-ray sources closest to the optical position and calculated their X-ray luminosity, LX, and X-ray colours. Using Halpha luminosities, we also calculated star formation rates. For four sources with a high number of net counts in the X-ray band, we extracted X-ray spectra to which we fitted standard spectral models. We modelled Fe Kalpha emission by Gaussians, and assessed the significance of adding such a component to a fit by means of a calibration of the standard F-test. For the rest of the sources, we estimated values for the intrinsic hydrogen column density, Nintverb++++H_, and the power-law photon index, Γ, which can reproduce the observed soft and hard X-ray colours. All spectral fits include a power law, a diffuse hot gas, a Galactic absorption and an intrinsic absorption component. For the nuclear sources of NGC 2782 and NGC 3310, a Fe Kalpha emission-line component is included with high significance. At the same time the power-law component is flat (index Γ∼0 and 1.3). Both sources have high star-formation rates, with the rate for NGC 2782 being the highest in our sample. The detection of Fe Kalpha emission coming from a central, isolated source in NGC 2782 and NGC 3310, points towards a hidden AGN in two out of nine relatively early-type, star-forming spirals observed both with Palomar and Chandra. Larger samples need to be explored, but this evidence suggests that the presence of an AGN is likely in massive, disturbed starbursts. The contribution of X-ray emission from these AGN is small: For the central source, the bolometric luminosity is a fraction of a fewx10–5 of the Eddington luminosity. The X-ray flux of the central source is between 10 and 20% of the total galactic flux in the 0.2-10keV band.

Abstract Copyright:

Journal keyword(s): X-rays: galaxies - galaxies: starburst - galaxies: active - galaxies: individual: NGC 2782 - galaxies: individual: NGC 3310

Nomenclature: Table 2: [TG2007] JHHMMSS.s+DDMMSS.s N=11, [TG2007] NGC NNNNA (Nos NGC 278U, 278L, 4217U, 4217L).

Simbad objects: 26

goto Full paper

goto View the reference in ADS

Number of rows : 26

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 NGC 102 GiG 00 24 36.5421526931 -13 57 22.849378671   14   13.62   ~ 17 0
2 NGC 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 2857 2
3 NGC 278 H2G 00 52 04.3422973787 +47 33 01.649350749   10.5       ~ 215 1
4 [TG2007] NGC 278L HXB 00 52 04.4 +47 32 58   11.5       ~ 2 0
5 [TG2007] NGC 278U HXB 00 52 04.4 +47 33 04   11.5       ~ 2 0
6 NGC 660 LIN 01 43 02.350 +13 38 44.45   12.02 11.16     ~ 501 2
7 [TG2007] J022232.9+422045 X 02 22 32.9 +42 20 45   10.9       ~ 1 0
8 NGC 891 H2G 02 22 32.907 +42 20 53.95 11.08 10.81 9.93 7.86   ~ 1490 2
9 [TG2007] J061837.6+782120 X 06 18 37.6 +78 21 20   11.2       ~ 1 0
10 NGC 2146 SBG 06 18 37.710 +78 21 25.27 11.67 11.38 10.59     ~ 602 2
11 [TG2007] J091405.1+400647 X 09 14 05.1 +40 06 47   12.1       ~ 1 0
12 NGC 2782 Sy2 09 14 05.120 +40 06 49.68 12.29 12.30 11.63     ~ 428 3
13 [TG2007] J103845.8+533011 X 10 38 45.8 +53 30 11   11.2       ~ 1 0
14 NGC 3310 AGN 10 38 45.857 +53 30 11.89   12.45 12.15     ~ 720 1
15 NAME NGC 3690 West GiP 11 28 30.69 +58 33 33.4   11.8       ~ 603 4
16 NGC 3690 IG 11 28 31.326 +58 33 41.80   13.19 12.86     ~ 864 4
17 NAME NGC 3690 East AGN 11 28 33.07 +58 33 54.2   11.8       ~ 608 4
18 [TG2007] NGC 4102 X 12 06 23.0 +52 42 40   12.3       ~ 1 0
19 NGC 4102 LIN 12 06 23.115 +52 42 39.42   11.8       ~ 363 1
20 [TG2007] J121550.8+470532 X 12 15 50.8 +47 05 32   10.9       ~ 1 0
21 NGC 4217 GiG 12 15 50.900 +47 05 30.44   12.4       ~ 243 2
22 [TG2007] NGC 4217L X 12 15 51.0 +47 05 29   10.9       ~ 1 0
23 [TG2007] J122154.9+042825 X 12 21 54.9 +04 28 25   10.1       ~ 1 0
24 M 61 Sy2 12 21 54.9275149050 +04 28 25.588335799 10.07 10.18 9.65     ~ 852 2
25 [TG2007] J151523.3+553102 X 15 15 23.32 +55 31 02.0   12.3       ~ 2 0
26 NGC 5905 H2G 15 15 23.324 +55 31 01.59   13.6       ~ 243 1

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2007A&A...468..129T and select 'bookmark this link' or equivalent in the popup menu


2019.10.19-00:40:23

© Université de Strasbourg/CNRS

    • Contact