ENVIRONMENTAL EFFECTS IN THE EVOLUTION OF GALACTIC BULGES

Journal Article · Wed Jan 20 04:00:00 EST 2010 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/709/1/L53; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21301394

MacArthur, Lauren A ^[1]; Ellis, Richard S ^[2]; Treu, Tommaso ^[3]

---

1. Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V8X 4M6 (Canada)
2. Department of Astrophysics, California Institute of Technology, MS 105-24, Pasadena, CA 91125 (United States)
3. Department of Physics, University of California, Santa Barbara, CA 93106-9530 (United States)

We investigate possible environmental trends in the evolution of galactic bulges over the redshift range 0 < z < 0.6. For this purpose, we construct the fundamental plane (FP) for cluster and field samples at redshifts (z) = 0.4 and (z) = 0.54 using surface photometry based on Hubble Space Telescope imaging and velocity dispersions based on Keck spectroscopy. As a reference point for our study, we include data for pure ellipticals, which we model as single-component Sersic profiles; whereas for multi-component galaxies we undertake decompositions using Sersic and exponential models for the bulge and disk, respectively. Although the FP for both distant cluster and field samples is offset from the local relation, consistent with evolutionary trends found in earlier studies, we detect significant differences in the zero point of {approx_equal}0.2 dex between the field and cluster samples at a given redshift. For both clusters, the environmentally dependent offset is in the sense expected for an accelerated evolution of bulges in dense environments. By matching the mass range of our samples, we confirm that this difference does not arise as a result of the mass-dependent downsizing effects seen in larger field samples. Our result is also consistent with the hypothesis that-at fixed mass and environment-the star formation histories of galactic bulges and pure spheroids are indistinguishable and difficult to reconcile with the picture whereby the majority of large bulges form primarily via secular processes within spiral galaxies.

• OSTI ID: 21301394
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 709; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
99 GENERAL AND MISCELLANEOUS
GALACTIC EVOLUTION
GALAXIES
MASS
PHOTOMETRY
RED SHIFT
SPECTROSCOPY
SPHEROIDS
STARS
TELESCOPES