2014A&A...569A..26H


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.21CEST08:39:56

2014A&A...569A..26H - Astronomy and Astrophysics, volume 569A, 26-26 (2014/9-1)

X-ray spectral variability of LINERs selected from the Palomar sample.

HERNANDEZ-GARCIA L., GONZALEZ-MARTIN O., MASEGOSA J. and MARQUEZ I.

Abstract (from CDS):

Variability is a general property of active galactic nuclei (AGN). The way in which these changes occur at X-rays is not yet clearly understood. In the particular case of low-ionization nuclear emission line region (LINER) nuclei, variations on the timescales from months to years have been found for some objects, but the main driver of these changes is still debated. The main purpose of this work is to investigate the X-ray variability in LINERs, including the main driver of these variations, and to search for possible differences between type 1 and 2 objects. We examined the 18 LINERs in the Palomar sample with data retrieved from the Chandra and/or XMM-Newton archives that correspond to observations gathered at different epochs. All the spectra for the same object were fitted simultaneously to study long-term variations. The nature of the variability patterns were studied by allowing different parameters to vary during the spectral fit. Whenever possible, short-term variations from the analysis of the light curves and long-term UV variability were studied. Short-term variations are not reported in X-rays. Three LINERs are classified as non-AGN candidates in X-rays, all of them are Compton-thick candidates; none of them show variations at these frequencies, and two of them vary in the UV. Long-term X-ray variations were analyzed in 12 out of 15 AGN candidates; about half of them showed variability (7 out of the 12). At UV frequencies, most of the AGN candidates with available data are variable (five out of six). Thus, 13 AGN candidates are analyzed at UV and/or X-rays, ten of which are variable at least in one energy band. None of the three objects that do not vary in X-rays have available UV data. This means that variability on long-timescales is very common in LINERs. These X-ray variations are mainly driven by changes in the nuclear power, while changes in absorptions are found only for NGC1052. We do not find any difference between type 1 and 2 LINERs, neither in the number of variable cases (three out of five type 1 and four out of seven type 2 LINERs), nor in the nature of the variability pattern. We find indications of an anticorrelation between the slope of the power law, Γ, and the Eddington ratio. LINERs are definitely variable sources irrespective of whether they are classified as optical type 1 or 2. Their BH masses, accretion rates, and variability timescales place them in the same plane as more powerful AGN at X-rays. However, our results suggest that the accretion mechanism in LINERs may be different. UV variations of some type 2 LINERs were found, this could support the hypothesis of a torus that disappears at low luminosities.

Abstract Copyright:

Journal keyword(s): galaxies: active - X-rays: galaxies - ultraviolet: galaxies

Simbad objects: 40

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Number of rows : 40

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 315 LIN 00 57 48.88335 +30 21 08.8122 12.80 12.20 11.16 11.26   ~ 683 2
2 ZwCl 0107+3212 ClG 01 10.3 +32 28     12.14     ~ 22 0
3 NGC 1052 GiP 02 41 04.79851 -08 15 20.7517 11.84 11.41 10.47 10.71   ~ 1102 2
4 NGC 1365 Sy1 03 33 36.458 -36 08 26.37 10.48 10.08 9.63 8.79 9.7 ~ 1473 2
5 NGC 1961 LIN 05 42 04.775 +69 22 42.17   11.73 10.99     ~ 298 3
6 Mrk 3 Sy2 06 15 36.458 +71 02 15.24 14.21 14.03 12.97     ~ 826 3
7 NGC 2681 LIN 08 53 32.739 +51 18 49.35 11.40 11.09 10.29     ~ 295 1
8 NGC 2787 LIN 09 19 18.6043000282 +69 12 11.642887220   12.92 11.79     ~ 305 0
9 NGC 2841 LIN 09 22 02.655 +50 58 35.32 10.43 10.09 9.22     ~ 964 1
10 NGC 3226 GiP 10 23 27.0067240562 +19 53 54.682329315   14.32 13.33     ~ 389 1
11 NGC 3227 GiP 10 23 30.57 +19 51 54.3   12.61 11.79     ~ 1494 2
12 [VV2006] J111654.8+180304 QSO 11 16 54.657 +18 03 06.51   13.84 12.76     ~ 426 0
13 NGC 3608 LIN 11 16 58.967 +18 08 54.71   11.7       ~ 467 0
14 NAME NGC 3607 Group GrG 11 17 55.9 +18 07 35   9.9       ~ 50 0
15 NGC 3718 GiP 11 32 34.8527469396 +53 04 04.494313634   11.35 10.61     ~ 334 1
16 NGC 4102 LIN 12 06 23.115 +52 42 39.42   11.8       ~ 363 1
17 NGC 4151 Sy1 12 10 32.5771747733 +39 24 21.057727323   12.18 11.48     ~ 3306 2
18 NGC 4253 Sy1 12 18 26.5155239433 +29 48 46.518670434   14.34 13.57     ~ 912 1
19 NGC 4261 LIN 12 19 23.21607184 +05 49 29.7000920   13.92 12.87     ~ 1089 0
20 NGC 4278 LIN 12 20 06.82563 +29 16 50.7124 11.54 11.09 10.16     ~ 875 2
21 M 84 Sy2 12 25 03.74333 +12 53 13.1393 12.67 12.09 10.49     ~ 1609 2
22 NAME Vir I ClG 12 26 32.1 +12 43 24   10.00 8.49     ~ 5645 0
23 M 87 BiC 12 30 49.42338230 +12 23 28.0438581 10.16 9.59 8.63   7.49 ~ 6026 3
24 NGC 4494 GiP 12 31 24.034 +25 46 29.93   10.55 9.74     ~ 444 0
25 M 89 LIN 12 35 39.8 +12 33 23 11.29 10.73 9.75     ~ 906 2
26 NGC 4636 LIN 12 42 49.867 +02 41 16.01   12.62 11.84     ~ 1025 1
27 [WMR2006] NGC4736 XMM1 X 12 50 50.3 +41 07 12           ~ 11 0
28 [SST2011] J125052.72+410719.0 UX? 12 50 52.72 +41 07 19.0           ~ 9 0
29 [BWC2008] C14 X 12 50 53.1 +41 07 13           ~ 8 0
30 M 94 SyG 12 50 53.148 +41 07 12.55 9.15 8.96 8.24 7.78   ~ 1181 3
31 [ESC2002] NGC 4736 X-1 ULX 12 50 53.3 +41 07 14           ~ 9 0
32 M 51 GiP 13 29 52.698 +47 11 42.93   9.26 8.36 8.40   ~ 3683 4
33 NGC 5195 GiP 13 29 59.590 +47 15 58.06 10.76 10.45 9.55 9.31   ~ 683 3
34 NGC 5813 LIN 15 01 11.265 +01 42 07.09 12.00 11.45 10.46 10.06   ~ 564 1
35 NGC 5846 BiC 15 06 29.253 +01 36 20.29   11.9   9.74   ~ 755 1
36 NGC 5892 EmG 15 13 48.1987963599 -15 27 49.558463839   12.0   11.80 12.3 ~ 53 0
37 NGC 5982 LIN 15 38 39.778 +59 21 21.21   12.4       ~ 273 0
38 MAXI J1910-057 LXB 19 10 22.80 -05 47 55.9           ~ 46 0
39 IRAS 21262+5643 Sy1 21 27 45.3943647524 +56 56 34.913660916       16.6   ~ 124 0
40 NGC 7213 Sy1 22 09 16.2106632887 -47 10 00.082166299   10.97 12.08 10.50 10.6 ~ 572 0

    Equat.    Gal    SGal    Ecl

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2019.10.21-08:39:56

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