Search Publications
Evidence for Morphology and Luminosity Transformation of Galaxies at High Redshifts
Hwang, Ho Seong; Park, Changbom
We study the galaxy morphology-luminosity-environmental relation and its redshift evolution using a spectroscopic sample of galaxies in the Great Observatories Origins Deep Survey. In the redshift range of 0.4 <= z <= 1.0, we detect conformity in morphology between neighboring galaxies. The realm of conformity is confined within the virializ…
Classification of Extremely Red Objects in the Cosmos Field
Fang, Guanwen; Kong, Xu; Wang, Min +1 more
We present a study of the classification of z ~ 1 extremely red objects (EROs), using a combination of Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS), Spitzer Infrared Array Camera (IRAC), and ground-based images of the COSMOS field. Our sample includes ~5300 EROs with i - K s >= 2.45 (AB, equivalently I - K s
Vector Magnetic Fields of Solar Granulation
Wang, Jingxiu; Jin, Chunlan; Zhao, Meng
Observations of the quiet Sun from the Solar Optical Telescope/Spectro-Polarimeter aboard the Hinode spacecraft reveal the magnetic characteristics of the solar photosphere. By making use of the deep-mode observations of three quiet regions, we have statistically studied the vector magnetic fields of solar granulation. More than 2000 normal granul…
Star Formation History of the Small Magellanic Cloud: Six Hubble Space Telescope/Advanced Camera for Survey Fields
Da Costa, G. S.; Anderson, J.; Cignoni, M. +9 more
We observed six fields of the Small Magellanic Cloud (SMC) with the Advanced Camera for Survey on board the Hubble Space Telescope in the F555W and F814W filters. These fields sample regions characterized by very different star and gas densities, and, possibly, by different evolutionary histories. We find that the SMC was already forming stars ~12…
Can the Composition of the Solar Corona Be Derived from Hinode/Extreme-Ultraviolet Imaging Spectrometer Spectra?
Doschek, G. A.; Warren, H. P.; Brown, C. M. +1 more
Elemental abundances appear to be the same everywhere in the photosphere, but in the solar corona they vary in different regions. Abundances in quiet Sun (closed) flux tubes are different from those in coronal hole (CH, open) magnetic field regions, and therefore abundance variations might possibly be used to determine locations of slow and fast s…
A Universal Decline Law of Classical Novae. IV. V838 Her (1991): A Very Massive White Dwarf
Cassatella, Angelo; Kato, Mariko; Hachisu, Izumi
We present a unified model of optical and ultraviolet (UV) light curves for one of the fastest classical novae, V838 Herculis (Nova Herculis 1991), and estimate its white dwarf (WD) mass. Based on an optically thick wind theory of nova outbursts, we model the optical light curves with free-free emission and the UV 1455 Å light curves with blackbod…
Discovery of C IV Emission Filaments in M87
Sparks, W. B.; Pringle, J. E.; Donahue, M. +4 more
Gas at intermediate temperatures between the hot X-ray-emitting coronal gas in galaxies at the centers of galaxy clusters and the much cooler optical line emitting filaments yields information on transport processes and plausible scenarios for the relationship between X-ray cool cores and other galactic phenomena such as mergers or the onset of an…
Probing the Accretion Disk and Central Engine Structure of NGC 4258 with Suzaku and XMM-Newton Observations
Reynolds, Christopher S.; Young, Andrew J.; Nowak, Michael A. +3 more
We present an X-ray study of the low-luminosity active galactic nucleus (AGN) in NGC 4258 using data from Suzaku, XMM-Newton, and the Swift/Burst Alert Telescope survey. We find that signatures of X-ray reprocessing by cold gas are very weak in the spectrum of this Seyfert-2 galaxy; a weak, narrow fluorescent Kα emission line of cold iron is robus…
Detection of Supersonic Horizontal Flows in the Solar Granulation
Bellot Rubio, L. R.
Hydrodynamic simulations of granular convection predict the existence of supersonic flows covering ~3%-4% of the solar surface at any time, but these flows have not been detected unambiguously as yet. Using data from the spectropolarimeter aboard the Hinode satellite, I present direct evidence of fast horizontal plasma motions in quiet-Sun granule…
Dust Distribution in the β Pictoris Circumstellar Disks
Artymowicz, Pawel; Croll, Bryce; Ahmic, Mirza
We present three-dimensional models of dust distribution around β Pictoris that produce the best fits to the Hubble Space Telescope/Advanced Camera for Surveys' images obtained by Golimowski and coworkers. We allow for the presence of either one or two separate axisymmetric dust disks. The density models are analytical, radial two power laws joine…