Deep ROSAT HRI observations of the NGC 1399/NGC 1404 region: Morphology and structure of the X-ray halo

Giovanni Peres, Kim, Fabbiano, Maurizio Paolillo

Risultato della ricerca: Article

74 Citazioni (Scopus)

Abstract

We present the analysis of a deep (167 ks) ROSAT HRI observation of the cD galaxy NGC 1399 in the Fornax Cluster, comparing it with previous work on this galaxy and with recent Chandra data. We find, in agreement with previous observations, an extended and asymmetric gaseous halo with a luminosity (in the 0.1-2.4 keV energy band) of Lx = (5.50 ± 0.04) × 1041 ergs s-1 within 46 kpc (assuming a distance of D = 19 Mpc). Using both HRI and, at larger radii, archival PSPC data, we find that the radial behavior of the X-ray surface brightness profile is not consistent with a simple β-model and suggests instead three distinct components. We use a multicomponent bidimensional model to study in detail these three components, which we identify respectively with the cooling flow region, the galactic halo, and the cluster halo. From these data we derive a binding mass distribution in agreement with that suggested by optical dynamical indicators, with an inner core dominated by luminous matter and an extended dark halo differently distributed on galactic and cluster scales. The HRI data and a preliminary analysis of Chandra public data allow us to detect significant density fluctuations in the halo. We discuss possible nonequilibrium scenarios to explain the hot halo structure, including tidal interactions with neighboring galaxies, ram stripping from the intracluster medium, and merging events. In the innermost region of NGC 1399, the comparison between the X-ray and radio emission suggests that the radio-emitting plasma is displacing and producing shocks in the hot X-ray-emitting gas. We do not detect the nuclear source in X-rays, and we pose an upper limit of ∼4 × 1039 ergs s-1 (0.1-2.4 keV) to its X-ray luminosity. We found that the NGC 1404 halo is well represented by a single symmetric β-model and follows the stellar light profile within the inner 8 kpc. The mass distribution is similar to the "central" component of the NGC 1399 halo. At larger radii, ram pressure stripping from the intracluster gas produces strong asymmetries in the galactic halo. Finally, we discuss the properties of the point-source population, finding evidence of correlation between the source excess and NGC 1399.
Lingua originaleEnglish
pagine (da-a)883-907
Numero di pagine25
RivistaDefault journal
Volume565
Stato di pubblicazionePublished - 2002

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halos
x rays
erg
ram
galactic halos
galaxies
stripping
mass distribution
radio
inner core
luminosity
gas
point source
radii
asymmetry
radio emission
profiles
gases
cooling
point sources

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cita questo

Deep ROSAT HRI observations of the NGC 1399/NGC 1404 region: Morphology and structure of the X-ray halo. / Peres, Giovanni; Kim; Fabbiano; Paolillo, Maurizio.

In: Default journal, Vol. 565, 2002, pag. 883-907.

Risultato della ricerca: Article

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title = "Deep ROSAT HRI observations of the NGC 1399/NGC 1404 region: Morphology and structure of the X-ray halo",
abstract = "We present the analysis of a deep (167 ks) ROSAT HRI observation of the cD galaxy NGC 1399 in the Fornax Cluster, comparing it with previous work on this galaxy and with recent Chandra data. We find, in agreement with previous observations, an extended and asymmetric gaseous halo with a luminosity (in the 0.1-2.4 keV energy band) of Lx = (5.50 ± 0.04) × 1041 ergs s-1 within 46 kpc (assuming a distance of D = 19 Mpc). Using both HRI and, at larger radii, archival PSPC data, we find that the radial behavior of the X-ray surface brightness profile is not consistent with a simple β-model and suggests instead three distinct components. We use a multicomponent bidimensional model to study in detail these three components, which we identify respectively with the cooling flow region, the galactic halo, and the cluster halo. From these data we derive a binding mass distribution in agreement with that suggested by optical dynamical indicators, with an inner core dominated by luminous matter and an extended dark halo differently distributed on galactic and cluster scales. The HRI data and a preliminary analysis of Chandra public data allow us to detect significant density fluctuations in the halo. We discuss possible nonequilibrium scenarios to explain the hot halo structure, including tidal interactions with neighboring galaxies, ram stripping from the intracluster medium, and merging events. In the innermost region of NGC 1399, the comparison between the X-ray and radio emission suggests that the radio-emitting plasma is displacing and producing shocks in the hot X-ray-emitting gas. We do not detect the nuclear source in X-rays, and we pose an upper limit of ∼4 × 1039 ergs s-1 (0.1-2.4 keV) to its X-ray luminosity. We found that the NGC 1404 halo is well represented by a single symmetric β-model and follows the stellar light profile within the inner 8 kpc. The mass distribution is similar to the {"}central{"} component of the NGC 1399 halo. At larger radii, ram pressure stripping from the intracluster gas produces strong asymmetries in the galactic halo. Finally, we discuss the properties of the point-source population, finding evidence of correlation between the source excess and NGC 1399.",
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TY - JOUR

T1 - Deep ROSAT HRI observations of the NGC 1399/NGC 1404 region: Morphology and structure of the X-ray halo

AU - Peres, Giovanni

AU - Kim, null

AU - Fabbiano, null

AU - Paolillo, Maurizio

PY - 2002

Y1 - 2002

N2 - We present the analysis of a deep (167 ks) ROSAT HRI observation of the cD galaxy NGC 1399 in the Fornax Cluster, comparing it with previous work on this galaxy and with recent Chandra data. We find, in agreement with previous observations, an extended and asymmetric gaseous halo with a luminosity (in the 0.1-2.4 keV energy band) of Lx = (5.50 ± 0.04) × 1041 ergs s-1 within 46 kpc (assuming a distance of D = 19 Mpc). Using both HRI and, at larger radii, archival PSPC data, we find that the radial behavior of the X-ray surface brightness profile is not consistent with a simple β-model and suggests instead three distinct components. We use a multicomponent bidimensional model to study in detail these three components, which we identify respectively with the cooling flow region, the galactic halo, and the cluster halo. From these data we derive a binding mass distribution in agreement with that suggested by optical dynamical indicators, with an inner core dominated by luminous matter and an extended dark halo differently distributed on galactic and cluster scales. The HRI data and a preliminary analysis of Chandra public data allow us to detect significant density fluctuations in the halo. We discuss possible nonequilibrium scenarios to explain the hot halo structure, including tidal interactions with neighboring galaxies, ram stripping from the intracluster medium, and merging events. In the innermost region of NGC 1399, the comparison between the X-ray and radio emission suggests that the radio-emitting plasma is displacing and producing shocks in the hot X-ray-emitting gas. We do not detect the nuclear source in X-rays, and we pose an upper limit of ∼4 × 1039 ergs s-1 (0.1-2.4 keV) to its X-ray luminosity. We found that the NGC 1404 halo is well represented by a single symmetric β-model and follows the stellar light profile within the inner 8 kpc. The mass distribution is similar to the "central" component of the NGC 1399 halo. At larger radii, ram pressure stripping from the intracluster gas produces strong asymmetries in the galactic halo. Finally, we discuss the properties of the point-source population, finding evidence of correlation between the source excess and NGC 1399.

AB - We present the analysis of a deep (167 ks) ROSAT HRI observation of the cD galaxy NGC 1399 in the Fornax Cluster, comparing it with previous work on this galaxy and with recent Chandra data. We find, in agreement with previous observations, an extended and asymmetric gaseous halo with a luminosity (in the 0.1-2.4 keV energy band) of Lx = (5.50 ± 0.04) × 1041 ergs s-1 within 46 kpc (assuming a distance of D = 19 Mpc). Using both HRI and, at larger radii, archival PSPC data, we find that the radial behavior of the X-ray surface brightness profile is not consistent with a simple β-model and suggests instead three distinct components. We use a multicomponent bidimensional model to study in detail these three components, which we identify respectively with the cooling flow region, the galactic halo, and the cluster halo. From these data we derive a binding mass distribution in agreement with that suggested by optical dynamical indicators, with an inner core dominated by luminous matter and an extended dark halo differently distributed on galactic and cluster scales. The HRI data and a preliminary analysis of Chandra public data allow us to detect significant density fluctuations in the halo. We discuss possible nonequilibrium scenarios to explain the hot halo structure, including tidal interactions with neighboring galaxies, ram stripping from the intracluster medium, and merging events. In the innermost region of NGC 1399, the comparison between the X-ray and radio emission suggests that the radio-emitting plasma is displacing and producing shocks in the hot X-ray-emitting gas. We do not detect the nuclear source in X-rays, and we pose an upper limit of ∼4 × 1039 ergs s-1 (0.1-2.4 keV) to its X-ray luminosity. We found that the NGC 1404 halo is well represented by a single symmetric β-model and follows the stellar light profile within the inner 8 kpc. The mass distribution is similar to the "central" component of the NGC 1399 halo. At larger radii, ram pressure stripping from the intracluster gas produces strong asymmetries in the galactic halo. Finally, we discuss the properties of the point-source population, finding evidence of correlation between the source excess and NGC 1399.

UR - http://hdl.handle.net/10447/232464

UR - http://iopscience.iop.org/0004-637X/

M3 - Article

VL - 565

SP - 883

EP - 907

JO - Default journal

JF - Default journal

ER -