2011A&A...533A..56P


Query : 2011A&A...533A..56P

2011A&A...533A..56P - Astronomy and Astrophysics, volume 533A, 56-56 (2011/9-1)

The deeply obscured AGN of NGC 4945. I. Spitzer-IRS maps of [Ne v], [Ne II], H2 0-0 S(1), S(2), and other tracers.

PEREZ-BEAUPUITS J.P., SPOON H.W.W., SPAANS M. and SMITH J.D.

Abstract (from CDS):

The nearly edge-on galaxy NGC 4945 is one of the closest galaxies where an AGN and starburst coexist, and is one of the brightest sources at 100 keV. Near and mid-infrared spectroscopy have shown very strong obscuration of its central region, rivaled only in strength by some of the most deeply obscured ULIRGs. We determine the spatial distribution of ISM emission features in the central 426x426pc2 of NGC 4945. We mapped the central region of NGC 4945 in three of the four Spitzer-IRS modules (SH, SL and LL). In particular, we produced maps of the flux distribution of the starburst tracers [NeII], [NeIII], [SIII] and [SIV] at 12.81, 15.56, 18.71, and 10.51µm, respectively, and a map of the AGN narrow-line region tracer [NeV] at 14.32µm. In addition, we mapped the S(1), S(2), and S(3) pure rotational lines of H2, which trace the distribution of warm molecular hydrogen. Finally, we obtained an extinction map (AV) based on the apparent strength of the 9.7µm silicate absorption feature. At a spatial resolution of ∼5", our extinction map traces the contours of the starburst ring. The highest extinction is, however, found at the nucleus, where we measure AV(9.85µm)≃60. Within the uncertainty of the astrometry, all emission lines are found to peak on the nucleus, except for the warm molecular hydrogen emission, which shows a maximum 60-100 pcNW of the nucleus. We favor a scenario in which the emission of the lower H2 0-0 S(1) and S(2) rotational lines originate mainly in an unobscured extranuclear component associated with the super-wind cone observed in the HST NICMOS map of the H2 1-0 S(1) vibrational line. For the [NeV] emission we infer an attenuation of a factor 12-160 (AV=55-112) based on a comparison of the ratio of our [NeV] flux and the absorption-corrected 14-195keV Swift-BAT flux to the average [NeV]/BAT ratio for Seyfert 1 nuclei. The high attenuation indicates that [NeV] and [OIV] cannot be used as extinction-free tracers of AGN power in galaxies with deeply buried nuclei.

Abstract Copyright:

Journal keyword(s): galaxies: active - galaxies: nuclei - galaxies: individual: NGC 4945 - ISM: lines and bands

Simbad objects: 19

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Number of rows : 19
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 IRAS F00183-7111 Sy2 00 20 34.7 -70 55 27     20.6     ~ 129 0
2 NGC 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 3162 2
3 SNR B0102-72.3 SNR 01 04 01.2 -72 01 52           ~ 376 1
4 M 77 GiP 02 42 40.7091669408 -00 00 47.859690204 9.70 9.61 8.87 10.1 9.9 ~ 4380 2
5 NGC 1365 Sy1 03 33 36.458 -36 08 26.37 10.48 10.08 9.63 8.79 9.7 ~ 1661 2
6 NGC 1377 GiG 03 36 39.077 -20 54 08.14   13.38   12.12   ~ 211 0
7 NAME IRAS F08572+3915 NW LIN 09 00 25.364 +39 03 54.23     16.66     ~ 396 1
8 M 82 IG 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5636 6
9 NGC 3079 Sy2 10 01 57.8789863992 +55 40 47.449758324 11.57 11.54 10.86     ~ 1330 3
10 NGC 4355 Sy2 12 26 54.6206739120 -00 52 39.421212996   14.21 13.37     ~ 458 2
11 Mrk 231 Sy1 12 56 14.2341182928 +56 52 25.238373852   14.68 13.84     ~ 1914 3
12 NGC 4945 Sy2 13 05 27.279 -49 28 04.44   9.31 14.40 7.55   ~ 1383 2
13 NGC 5256 PaG 13 38 17.5 +48 16 37   14.1 13.42     ~ 418 1
14 IC 4553 SyG 15 34 57.22396 +23 30 11.6084   14.76 13.88     ~ 2847 4
15 NGC 6240 Sy2 16 52 58.861 +02 24 03.55   14.31 13.37     ~ 1572 2
16 WR 98a WR* 17 41 13.0411858104 -30 32 30.409373688   18.40   15.20 13.82 WC8/9 98 1
17 * P Cyg s*b 20 17 47.2020844 +38 01 58.552724 4.66 5.24 4.82 4.28 4.02 B1-2Ia-0ep 1155 1
18 NGC 7130 AGN 21 48 19.5412287192 -34 57 04.492024884   12.86 13.87 11.57   ~ 422 0
19 NAME Cas A SNR 23 23 24.000 +58 48 54.00     14.30     ~ 2632 1

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2022.09.30-20:48:53

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