2014A&A...563A.119B


C.D.S. - SIMBAD4 rel 1.7 - 2019.12.12CET01:49:34

2014A&A...563A.119B - Astronomy and Astrophysics, volume 563A, 119-119 (2014/3-1)

The HST view of the broad line region in low luminosity AGN.

BALMAVERDE B. and CAPETTI A.

Abstract (from CDS):

We analyze the properties of the broad line region (BLR) in low luminosity AGN by using HST/STIS spectra. We consider a sample of 24 nearby galaxies in which the presence of a BLR has been reported from their Palomar ground-based spectra. Following a widely used strategy, we used the [SII] doublet to subtract the contribution of the narrow emission lines to the Hα+[NII] complex and to isolate the BLR emission. Significant residuals that suggest a BLR, are present. However, the results change substantially when the [OI] doublet is used. Furthermore, the spectra are also reproduced well by just including a wing in the narrow Hα and [NII] lines, thus not requiring the presence of a BLR. We conclude that the complex structure of the narrow line region (NLR) is not captured with this approach and that it does not lead to general robust constraints on the properties of the BLR in these low-luminosity AGN. Nonetheless, the existence of a BLR is firmly established in 10 objects, 5 Seyferts, and 5 LINERs. However, the measured BLR fluxes and widths in the 5 LINERs differ substantially with respect to the ground-based data. The BLR sizes in LINERs, which are estimated by using the virial formula from the line widths and the black hole mass, are clustered between ∼500 and 2000 Schwarzschild radii (i.e., ∼5-100 light days). These values are ∼1 order of magnitude greater than the extrapolation to low luminosities of the relation between the BLR radius and AGN luminosity observed in more powerful active nuclei. We found BLR in objects with Eddington ratios as low as Lbol/LEdd∼10–5, with the faintest BLR having a luminosity of ∼1038>erg/s. This contrasts with theoretical models that predict the BLR disappearance at low luminosity. We ascribe the larger BLR radius to the lower accretion rate in LINERs when compared to the Seyfert, which causes the formation of an inner region dominated by an advection-dominated accretion flow (ADAF). The estimated BLR sizes in LINERs are comparable to the radius where the transition between the ADAF and the standard thin disk occurs due to disk evaporation. We suggest that BLR clouds cannot coexist with the hot inner region and that they only form in the correspondence with a thin accretion disk.

Abstract Copyright:

Journal keyword(s): galaxies: active - galaxies: Seyfert - galaxies: nuclei

Simbad objects: 26

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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 - 2020
#notes
1 NGC 315 LIN 00 57 48.88335 +30 21 08.8122 12.80 12.20 11.16 11.26   ~ 685 2
2 NGC 1052 GiP 02 41 04.79851 -08 15 20.7517 11.84 11.41 10.47 10.71   ~ 1109 2
3 3C 84 Sy2 03 19 48.1597607660 +41 30 42.114155434   13.10 12.48 11.09   ~ 3468 3
4 NGC 2787 LIN 09 19 18.6043000282 +69 12 11.642887220   12.92 11.79     ~ 306 0
5 NGC 2985 Sy1 09 50 22.233 +72 16 43.13   11.37 10.61     ~ 216 1
6 M 81 Sy2 09 55 33.17306143 +69 03 55.0609270   7.89 6.94     ~ 3899 5
7 NGC 3227 GiP 10 23 30.57 +19 51 54.3   12.61 11.79     ~ 1496 2
8 NGC 3516 Sy1 11 06 47.4596406816 +72 34 07.189563769   13.12 12.40     ~ 1392 0
9 NGC 3642 LIN 11 22 18.014 +59 04 27.27   14.86 14.04     ~ 184 0
10 NGC 3982 Sy1 11 56 28.169 +55 07 31.30   12.20 11.70 11.18   ~ 476 1
11 NGC 3998 SyG 11 57 56.1333561013 +55 27 12.925850484   11.64 12.10 10.09   ~ 560 2
12 NGC 4036 LIN 12 01 26.891 +61 53 44.52   12.18 11.20     ~ 225 0
13 NGC 4051 Sy1 12 03 09.6098828919 +44 31 52.693714606   11.08 12.92 9.94   ~ 1956 1
14 NGC 4143 LIN 12 09 36.086 +42 32 03.18   13.04 12.08     ~ 207 0
15 NGC 4151 Sy1 12 10 32.5771747733 +39 24 21.057727323   12.18 11.48     ~ 3315 2
16 NGC 4203 LIN 12 15 05.0543630359 +33 11 50.401356393   12.98 11.99     ~ 442 2
17 M 106 Sy2 12 18 57.620 +47 18 13.39   9.14 8.41 8.11   ~ 2063 3
18 NGC 4278 LIN 12 20 06.82563 +29 16 50.7124 11.54 11.09 10.16     ~ 876 2
19 NGC 4395 Sy2 12 25 48.8639154223 +33 32 48.694684028 10.84 10.54 10.11 9.98   ~ 958 1
20 NGC 4450 LIN 12 28 29.634 +17 05 05.82   10.90 10.08     ~ 502 1
21 M 58 SyG 12 37 43.597 +11 49 05.12 10.80 10.48 9.66     ~ 956 2
22 NGC 4636 LIN 12 42 49.867 +02 41 16.01   12.62 11.84     ~ 1027 1
23 NGC 5005 GiP 13 10 56.312 +37 03 32.19   14.67 13.67     ~ 489 2
24 NGC 5077 GiP 13 19 31.66964077 -12 39 25.0754790   13.87 12.85 11.30   ~ 263 0
25 NGC 5252 Sy2 13 38 15.8711551761 +04 32 33.525903711   15.21 14.21     ~ 410 0
26 NAME Serpens Dwarf GlC 15 16 05.30 -00 06 41.0   15.1       ~ 602 1

    Equat.    Gal    SGal    Ecl

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2019.12.12-01:49:34

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