2016A&A...585A.157P


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.03CEST23:09:31

2016A&A...585A.157P - Astronomy and Astrophysics, volume 585A, 157-157 (2016/1-1)

Hard X-ray emission of the luminous infrared galaxy NGC 6240 as observed by NuSTAR.

PUCCETTI S., COMASTRI A., BAUER F.E., BRANDT W.N., FIORE F., HARRISON F.A., LUO B., STERN D., URRY C.M., ALEXANDER D.M., ANNUAR A., AREVALO P., BALOKOVIC M., BOGGS S.E., BRIGHTMAN M., CHRISTENSEN F.E., CRAIG W.W., GANDHI P., HAILEY C.J., KOSS M.J., LA MASSA S., MARINUCCI A., RICCI C., WALTON D.J., ZAPPACOSTA L. and ZHANG W.

Abstract (from CDS):

We present a broadband (∼0.3-70keV) spectral and temporal analysis of NuSTAR observations of the luminous infrared galaxy NGC 6240 combined with archival Chandra, XMM-Newton, and BeppoSAX data. NGC 6240 is a galaxy in a relatively early merger state with two distinct nuclei separated by ∼1.5''. Previous Chandra observations resolved the two nuclei and showed that they are both active and obscured by Compton-thick material. Although they cannot be resolved by NuSTAR, we were able to clearly detect, for the first time, both the primary and the reflection continuum components thanks to the unprecedented quality of the NuSTAR data at energies >10keV. The NuSTAR hard X-ray spectrum is dominated by the primary continuum piercing through an absorbing column density which is mildly optically thick to Compton scattering (τ≃1.2, NH∼1.5x1024cm–2). We detect moderately hard X-ray (>10keV) flux variability up to 20% on short (15-20ks) timescales. The amplitude of the variability is largest at ∼30keV and is likely to originate from the primary continuum of the southern nucleus. Nevertheless, the mean hard X-ray flux on longer timescales (years) is relatively constant. Moreover, the two nuclei remain Compton-thick, although we find evidence of variability in the material along the line of sight with column densities NH≤2x1023cm–2 over long (∼3-15yr) timescales. The observed X-ray emission in the NuSTAR energy range is fully consistent with the sum of the best-fit models of the spatially resolved Chandra spectra of the two nuclei.

Abstract Copyright:

Journal keyword(s): galaxies: active - galaxies: individual: NGC 6240 - X-rays: galaxies

Simbad objects: 5

goto Full paper

goto View the reference in ADS

Number of rows : 5

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 M 77 GiP 02 42 40.771 -00 00 47.84 9.70 9.61 8.87 10.1 9.9 ~ 4098 2
2 NGC 1365 Sy1 03 33 36.458 -36 08 26.37 10.48 10.08 9.63 8.79 9.7 ~ 1530 2
3 Mrk 34 Sy2 10 34 08.606 +60 01 52.33   15.71 14.65     ~ 213 1
4 NGC 4945 Sy2 13 05 27.279 -49 28 04.44   9.31 14.40 7.55   ~ 1266 2
5 NGC 6240 Sy2 16 52 58.861 +02 24 03.55   14.31 13.37     ~ 1482 2

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2016A&A...585A.157P and select 'bookmark this link' or equivalent in the popup menu


2020.08.03-23:09:31

© Université de Strasbourg/CNRS

    • Contact