Engineering topics

Papovich, C.

Publications and source records attributed to Papovich, C..

3 records

NASA NTRS2010

The Morphology of Passively Evolving Galaxies at Z approximately 2 from HST/WFC3 Deep Imaging in the Hubble Ultradeep Field

We present near-IR images of six passive galaxies (SSFR< 10(exp -2)/ Gyr) at redshift 1.3 < z < 2.4 with stellar mass M approximately 10(exp 11) solar M, selected from the Great Observatories Origins Deep Survey (GOODS), obtained with the Hubble Space Telescope (HST) and the WFC3/IR camera. These images provide the deepest and highest angular resolution view of the optical rest-frame morphology of such systems to date. We find that the light profile of these galaxies is generally regular and well described by a Sersic model with index typical of today's spheroids. We confirm the existence of compact and massive early-type galaxies at z approximately 2: four out of six galaxies have r(sub e) approximately 1 kpc or less. The images reach limiting surface brightness mu approximates 26.5 mag/square arcsec in the F160W bandpass; yet there is no evidence of a faint halo in the galaxies of our sample, even in their stacked image. We also find very weak "morphological k-correction" in the galaxies between the rest-frame UV (from the ACS z-band), and the rest-frame optical (WFC3 H-band): the visual classification, Sersic indices and physical sizes of these galaxies are independent or only mildly dependent on the wavelength, within the errors. The presence of an active nucleus is suspected in two out of six galaxies (33%), opening the intriguing possibility that a large, presently unaccounted population of AGN is hosted in these galaxies, possibly responsible for the cessation of star formation.

Cassata, P.↗

NASA NTRS2009

The Morphology of Passively Evolving Galaxies at Z-2 from HST/WFC3 in the Hubble Ultra Deep Field

We discuss near-IR images of six passive galaxies (SSFR< 10(exp -2)/Gyr) at redshift 1.3 < z < 2.4 with stellar mass M approx 10(exp 11) solar mass, selected from the Great Observatories Origins Deep Survey (GOODS), obtained with WFC3/IR and the Hubble Space Telescope (HST). These WFC3 images provide the deepest and highest angular resolution view of the optical rest-frame morphology of such systems to date. We find that the light profile of these; galaxies is generally regular and well described by a Sersic model with index typical of today's spheroids. We confirm the existence of compact and massive early-type galaxies at z approx. 2: four out of six galaxies have T(sub e) approx. 1 kpc or less. The WFC3 images achieve limiting surface brightness mu approx. 26.5 mag/sq arcsec in the F160W bandpass; yet there is no evidence of a faint halo in the five compact galaxies of our sample, nor is a halo observed in their stacked image. We also find very weak "morphological k-correction" in the galaxies between the rest-frame UV (from the ACS z band), and the rest-frame optical (WFC3 H band): the visual classification, Sersic indices and physical sizes of these galaxies are independent or only mildly dependent on the wavelength, within the errors.

Cassata, P.↗

NASA NTRS2004

Extremely Red Objects in the Lockman Hole

We investigate extremely red objects (EROs) using near- and mid-infrared observations in five passbands (3.6 to 24 microns) obtained from the Spitzer Space Telescope, and deep ground-based R and K imaging. The great sensitivity of the Infrared Array Camera (IRAC) camera allows us to detect 64 EROs (a surface density of 2.90 +/- 0.36 arcmin(exp -2); [3.6](sub AB) is less than 23.7) in only 12 minutes of IRAC exposure time, by means of an R - [3.6] color cut (analogous to the traditional red R - K cut). A pure infrared K - [3.6] red cut detects a somewhat different population and may be more effective at selecting z greater than 1.3 EROs. We find approximately 17% of all galaxies detected by IRAC at 3.6 or 4.5 microns to be EROs. These percentages rise to about 40% at 5.8 microns, and about 60% at 8.0 microns. We utilize the spectral bump at 1.6 microns to divide the EROs into broad redshift slices using only near-infrared colors (2.2/3.6/4.5 microns). We conclude that two-thirds of all EROs lie at redshift z greater than 1.3. Detections at 24 microns imply that at least 11% of 0.6 less than z and less than 1.3 EROs and at least 22% of z greater than 1.3 EROs are dusty star-forming galaxies.

galaxies↗