Astronomy and Astrophysics – Astrophysics
Scientific paper
1997-02-03
Astronomy and Astrophysics
Astrophysics
AASTeX 4.0 (preprint), 4 PostScript figures
Scientific paper
10.1086/304730
We have previously found in the Hubble Deep Field a significant angular correlation of faint, high color-redshift objects on scales below one arcsecond, or several kiloparsecs in metric size. We examine the correlation and nearest neighbor statistics to conclude that 38% of these objects in the HDF have a companion within one arcsecond, three times the number expected in a random distribution with the same number of objects. We examine three dynamical scenarios for these object multiplets: 1) the objects are star-forming regions within normal galaxies, whose disks have been relatively dimmed by K-correction and surface brightness dimming; 2) they are fragments merging into large galaxies; 3) they are satellites accreting onto normal L_* galaxies. We find that hypothesis 1 is most tenable. First, large galaxies in the process of a merger formation would have accumulated too much mass in their centers (5e12 M_sun inside 2 kpc) to correspond to present day objects. Second, accretion by dynamical friction occurs with a predictable density vs. radius slope, not seen among the faint HDF objects. Since the dynamical friction time is roughly (1 Gyr), a steady-state should have been reached by redshift z < 5. Star-forming regions within galaxies clearly present no dynamical problems. Since large spirals would still appear as such in the HDF, we favor a scenario in which the faint compact sources in the HDF are giant starforming regions within small normal galaxies, such as Magellanic irregulars. Finally we checked that reduction in mass-to-light from induced star-formation cannot alone explain the luminosity overdensity.
Colley Wesley N.
Gnedin Oleg Yuri
Ostriker Jeremiah P.
Rhoads James E.
No associations
LandOfFree
Dynamics of ``Small Galaxies'' in the Hubble Deep Field 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 Dynamics of ``Small Galaxies'' in the Hubble Deep Field, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamics of ``Small Galaxies'' in the Hubble Deep Field will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-223440