Astronomy and Astrophysics – Astronomy
Scientific paper
Apr 1995
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995apj...443...77m&link_type=abstract
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 443, no. 1, p. 77-88
Astronomy and Astrophysics
Astronomy
32
Accretion Disks, Astronomical Models, Elliptical Galaxies, Galactic Clusters, Luminosity, Radio Jets (Astronomy), Star Formation, Brightness, Color, Electromagnetic Wave Filters, Galactic Structure, Mass, Nebulae, Star Formation Rate
Scientific paper
We present new U- and I-band images of the centrally dominant galaxy in the Hydra A cluster, obtained with the 2.5 m Isaac Newton Telescope at La Palma. The galaxy is centered in a poor, X-ray-luminous cluster whose gaseous intracluster medium is apparently cooling at a rate of m-dotCF approximately 3000 solar masses/yr. The galaxy's structure is that of a normal giant elliptical galaxy, apart from the central approximately 8 x 6 arcsec (approximately 12 x 9 kpc) region which contains an unusually blue, lobelike structure that is spatially coincident with a luminous emission-line nebula in rotation about the nucleus. Based on near spatial coincidence of the central continuum structure and the emission-line nebula, we suggest that the blue continuum is due to a warm stellar population in a central disk. In order to isolate and study the structure of the disk, we have subtracted a smooth galactic background model from the U-band image. The disk's surface brightness profiles along its major and minor axes decline roughly exponentially with radius. The disk's axial ratio is consistent with a nearly edge-on thick disk or a thin disk that is inclined with respect to the line of sight. The bluest regions, located a few arcsec on either side of the nucleus (giving the lobelike appearance), may be due to locally enhanced star formation or a seeing-blurred ring of young stars embedded in the disk observed nearly edge-on. If star-formation is occurring with the local initial mass function, the central color, surface brightness, and dynamical mass would be consistent with models for star formation at a rate of less than and approximately 1 solar masses/yr which has persisted for the past approximately 109 yr, a short burst (107 yr) of star formation at a rate of approximately 30 solar masses/yr which occurred less than and approximately 108 yr ago, or an instantaneous burst of star formation which occurred approximately 5 x 107 yr ago. While the young population contributes approximately 30%-40% of the central U-band luminosity, its mass would be less than and approximately 1% to less than and approximately 10% (108 solar masses - 2 x 109 solar masses of the galaxy's central dynamical mass. We consider a number of possible origins for the disk material.
No associations
LandOfFree
Blue lobes in the Hydra A cluster central galaxy 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 Blue lobes in the Hydra A cluster central galaxy, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Blue lobes in the Hydra A cluster central galaxy will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1828504