BeppoSAX observations of LINER-2 galaxies

被引:17
作者
Georgantopoulos, I [1 ]
Panessa, F
Akylas, A
Zezas, A
Cappi, M
Comastri, A
机构
[1] Natl Observ Athens, Inst Astron & Astrophys, Athens 15236, Greece
[2] Univ Bologna, Dipartimento Astron, I-40127 Bologna, Italy
[3] CNR, Ist Technol & Studio Radiaz Extraterr, I-40129 Bologna, Italy
[4] Univ Athens, Dept Phys, Athens 15783, Greece
[5] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA
[6] Osservatorio Astron Bologna, I-40127 Bologna, Italy
关键词
galaxies : active; galaxies : starburst; X-rays : galaxies;
D O I
10.1051/0004-6361:20020078
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present BeppoSAX observations of 6 "type-2" LINER and "transition" galaxies (NGC 3379, NGC 3627, NGC 4125, NGC 4374, NGC 5195 and NGC 5879) from the Ho et al. (1997) spectroscopic sample of nearby galaxies. All objects are detected in the 2-10 keV band, having luminosities in the range L2-10 (keV) similar to 1 x 10(39)-1 x 10(40) erg s(-1). The PDS upper limits above 10 keV place constraints on the presence of a heavily obscured AGN in the case of NGC 3379 and NGC 4125. No significant variability is detected in any of the objects. The spectra are described in most cases by a simple power-law model with a spectral slope of Gamma similar to 1.7-2.5 while there is evidence neither for a significant absorption above the Galactic nor for an FeKalpha emission line. Therefore, based on the spectral properties alone, it is difficult to differentiate between a low-luminosity AGN or a star-forming galaxy scenario. However, imaging observations of NGC 3627 and NGC 5195 with Chandra ACIS-S reveal very weak nuclear sources while most of the X-ray flux originates either in off-nuclear point sources or in diffuse emission. The above clearly argue in favour of a star-forming origin for the bulk of the X-ray emission, at least in the above two sources.
引用
收藏
页码:60 / 68
页数:9
相关论文
共 47 条
[1]   SPECTROPOLARIMETRY AND THE NATURE OF NGC-1068 [J].
ANTONUCCI, RRJ ;
MILLER, JS .
ASTROPHYSICAL JOURNAL, 1985, 297 (02) :621-632
[2]   LINER/H II "transition" nuclei and the nature of NGC 4569 [J].
Barth, AJ ;
Shields, JC .
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC, 2000, 112 (772) :753-767
[3]   A search for ultraviolet emission from LINERs [J].
Barth, AJ ;
Ho, LC ;
Filippenko, AV ;
Sargent, WLW .
ASTROPHYSICAL JOURNAL, 1998, 496 (01) :133-+
[4]  
Bevington P., 2002, Data Reduction and Error Analysis for the Physical Sciences, V3rd ed.
[5]   The medium-energy concentrator spectrometer on board the BeppoSAX X-ray astronomy satellite [J].
Boella, G ;
Chiappetti, L ;
Conti, G ;
Cusumano, G ;
DelSordo, S ;
LaRosa, G ;
Maccarone, MC ;
Mineo, T ;
Molendi, S ;
Re, S ;
Sacco, B ;
Tripiciano, M .
ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES, 1997, 122 (02) :327-340
[6]   The hot gaseous halo of the spiral galaxy NGC 3628 in the Leo Triplet [J].
Dahlem, M ;
Heckman, TM ;
Fabbiano, G ;
Lehnert, MD ;
Gilmore, D .
ASTROPHYSICAL JOURNAL, 1996, 461 (02) :724-+
[7]   An X-ray minisurvey of nearby edge-on starburst galaxies. I. The data [J].
Dahlem, M ;
Weaver, KA ;
Heckman, TM .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1998, 118 (02) :401-453
[8]   H I IN THE GALAXY [J].
DICKEY, JM ;
LOCKMAN, FJ .
ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, 1990, 28 :215-261
[9]  
EHLE M, 1995, ASTRON ASTROPHYS, V295, P289
[10]   ROSAT PSPC OBSERVATIONS OF 2 DYNAMICALLY YOUNG ELLIPTIC GALAXIES - NGC-4125 AND NGC-3610 [J].
FABBIANO, G ;
SCHWEIZER, F .
ASTROPHYSICAL JOURNAL, 1995, 447 (02) :572-581