Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-01-25
Mon.Not.Roy.Astron.Soc. 358 (2005) 1423-1452
Astronomy and Astrophysics
Astrophysics
32 pages, 16 figures, accepted for publication in MNRAS, high resolution version available from ftp://ftp.atnf.csiro.au/pub/
Scientific paper
10.1111/j.1365-2966.2005.08862.x
(abridged) We present an analysis of Chandra X-ray observations of a sample of eight dwarf starburst galaxies (I Zw 18, VII Zw 403, NGC 1569, NGC 3077, NGC 4214, NGC 4449, NGC 5253, and He 2-10). Extended, diffuse X-ray emission is detected in all but two of the objects. Unresolved sources were found within all dwarf galaxies (total: 55 sources). These point sources are well fit by power law, thermal plasma, or black body models. Ten of the point sources exceed an X-ray luminosity of 10^39 erg s^-1 (ultraluminous X-ray sources). In those galaxies where diffuse X-ray emission is detected, this emission (with X-ray luminosities ranging from 4x10^38 erg s^-1 to 2x10^40 erg s^-1) contains most (60-80 per cent) of the X-ray photons. This diffuse emission can be well fit by MeKaL one-temperature thermal plasma models once the contribution from the unresolved point sources is subtracted properly. The diffuse X-ray component is significantly extended, reaching as far as 0.5-5 kpc into the outskirts of their hosts. Temperatures of various regions within the galaxies range from 1.6-7.6x10^6 K. With few exceptions, temperatures of the hot gas are remarkably uniform, hovering around 2-3x10^6 K. Temperatures of the coronal gas in the outer regions are in general ~2-3 times lower than those found in the central regions. Fits to the diffuse emission do not allow strong constraints to be put on the metallicities of the emitting plasmas. However, the derived metallicities are compatible with those determined from their HII regions. An alpha/Fe ratio of ~2 is indicated for the hot gas within at least three objects (NGC 1569, NGC 4449, and He 2-10).
Brinks Elias
Ott Juergen
Walter Fabian
No associations
LandOfFree
A Chandra X-ray survey of nearby dwarf starburst galaxies: I. Data reduction and results does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A Chandra X-ray survey of nearby dwarf starburst galaxies: I. Data reduction and results, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Chandra X-ray survey of nearby dwarf starburst galaxies: I. Data reduction and results will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-512827