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Full-Text Articles in Physical Sciences and Mathematics
An Isolated, Recently Shocked Ism Cloud In The Cygnus Loop Supernova Remnant, D. J. Patnaude, R. A. Fesen, J. C. Raymond, N. A. Levenson
An Isolated, Recently Shocked Ism Cloud In The Cygnus Loop Supernova Remnant, D. J. Patnaude, R. A. Fesen, J. C. Raymond, N. A. Levenson
Dartmouth Scholarship
Spatially resolved ROSAT X-ray and ground-based optical data for the southwestern region of the Cygnus Loop supernova remnant (SNR) reveal in unprecedented detail the very early stages of a blast-wave interaction with an isolated interstellar cloud. Numerous internal cloud shock fronts near the upstream flow and along the cloud edges are visible optically as sharp filaments of enhanced H emission. Faint X-ray emission is seen along a line of Balmer-dominated shock filaments north and south of the cloud with an estimated X-ray gas temperature of 1.2 106 K (0.11 keV), corresponding to a shock velocity of 290 km s1 . …
Spatially Resolved Spectroscopy Of Coma Cluster Early-Type Galaxies - Ii. The Minor Axis Dataset, G. Wegner, E. M. Corsini, R. P. Saglia, R. Bender
Spatially Resolved Spectroscopy Of Coma Cluster Early-Type Galaxies - Ii. The Minor Axis Dataset, G. Wegner, E. M. Corsini, R. P. Saglia, R. Bender
Dartmouth Scholarship
We present minor axis, offset major axis and one diagonal long slit spectra for 10 E and S0 galaxies of the Coma cluster drawn from a magnitude-limited sample studied before. We derive rotation curves, velocity dispersion profiles and the H3 and H4 coefficients of the Hermite decomposition of the line of sight velocity distribution. Moreover, we derive the line index profiles of Mg, Fe and Hβ line indices and assess their errors. The data will be used to construct dynamical models of the galaxies and study their stellar populations.
Extraordinary Late‐Time Infrared Emission Of Type Iin Supernovae, Christopher L. Gerardy, Robert A. Fesen, Ken-Ichi Nomoto, Peter M. Garnavich
Extraordinary Late‐Time Infrared Emission Of Type Iin Supernovae, Christopher L. Gerardy, Robert A. Fesen, Ken-Ichi Nomoto, Peter M. Garnavich
Dartmouth Scholarship
Near-infrared observations are presented for five Type IIn supernovae (SN 1995N, SN 1997ab, SN 1998S, SN 1999Z, and SN 1999el) that exhibit strong infrared excesses at late times (t > 100 days). H- and K-band emission from these objects is dominated by a continuum that rises toward longer wavelengths. The data are interpreted as thermal emission from dust, probably situated in a preexisting circumstellar nebula. The IR luminosities implied by single-temperature blackbody fits are quite large, >1041-1042 ergs s-1, and the emission evolves slowly, lasting for years after maximum light. For SN 1995N, the integrated energy release via …
Redshift-Distance Survey Of Early-Type Galaxies. I. The Enearc Cluster Sample*, M. Bernardi, M. V. Alonso, L. N. Da Costa, C. N. A. Willmer, A. Wegner
Redshift-Distance Survey Of Early-Type Galaxies. I. The Enearc Cluster Sample*, M. Bernardi, M. V. Alonso, L. N. Da Costa, C. N. A. Willmer, A. Wegner
Dartmouth Scholarship
This paper presents data on the ENEARc subsample of the larger ENEAR survey of nearby early-type galaxies. The ENEARc galaxies belong to clusters and were specifically chosen to be used for the construction of a D-n-sigma template. The ENEARc sample includes new measurements of spectroscopic and photometric parameters (redshift, velocity dispersion, line index Mg-2, and the angular diameter d(n)), as well as data from the literature. New spectroscopic data are given for 229 cluster early-type galaxies in 28 clusters. Objective criteria, based on catalogs of groups of galaxies derived from complete redshift surveys of the nearby universe, are used to …
Infrared Spectra Of The Subluminous Type Ia Supernova Sn 1999by, Peter Hoflich, Christopher L. Gerardy, Robert A. Fesen, Shoko Sakai
Infrared Spectra Of The Subluminous Type Ia Supernova Sn 1999by, Peter Hoflich, Christopher L. Gerardy, Robert A. Fesen, Shoko Sakai
Dartmouth Scholarship
Near-infrared (NIR) spectra of the subluminous Type Ia supernova SN 1999by are presented that cover the time evolution from about 4 days before to 2 weeks after maximum light. Analysis of these data was accomplished through the construction of an extended set of delayed detonation (DD) models covering the entire range of normal to subluminous SNe Ia. The explosion, light curves, and time evolution of the synthetic spectra were calculated self-consistently for each model, with the only free parameters being the initial structure of the white dwarf and the description of the nuclear burning front during the explosion. From these, …
Theoretical Uncertainties In The Subgiant--Mass Age Relation And The Absolute Age Of Omega Cen, Brian Chaboyer, Lawrence M. Krauss
Theoretical Uncertainties In The Subgiant--Mass Age Relation And The Absolute Age Of Omega Cen, Brian Chaboyer, Lawrence M. Krauss
Dartmouth Scholarship
The theoretical uncertainties in the calibration of the relationship between the subgiant mass and age in metal-poor stars are investigated using a Monte Carlo approach. Assuming that the mass and iron abundance of a subgiant star are known exactly, uncertainties in the input physics used to construct stellar evolution models and isochrones lead to a Gaussian 1 σ uncertainty of ±2.9% in the derived ages. The theoretical error budget is dominated by the uncertainties in the calculated opacities. Observations by Kałużny et al. of detached double-lined eclipsing binary OGLEGC 17 in the globular cluster ω Centauri have found that the …
Are Stars With Planets Polluted?, N. Murray, B. Chaboyer
Are Stars With Planets Polluted?, N. Murray, B. Chaboyer
Dartmouth Scholarship
We compare the metallicities of stars with radial velocity planets to the metallicity of a sample of field dwarfs. We confirm recent work indicating that the stars-with-planets sample as a whole is iron-rich. However, the lowest mass stars tend to be iron-poor, with several having [Fe/H] < -0.2, demonstrating that high metallicity is not required for the formation of short-period Jupiter-mass planets. We show that the average [Fe/H] increases with increasing stellar mass (for masses below 1.2 M☉) in both samples, but that the increase is much more rapid in the stars-with-planets sample. The variation of metallicity with stellar age also differs between the two samples. We examine possible selection effects related to variations in the sensitivity of radial velocity surveys with stellar mass, apparent magnitude, and stellar metallicity, and …