A5000945647- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Atmospheric Ozone and Climate
- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Solar and Space Plasma Dynamics
- Astrophysics and Cosmic Phenomena
- Calibration and Measurement Techniques
- Pulsars and Gravitational Waves Research
- Planetary Science and Exploration
- Spectroscopy and Laser Applications
- Space Exploration and Technology
- Scientific Research and Discoveries
- Atmospheric and Environmental Gas Dynamics
- Adaptive optics and wavefront sensing
- Photocathodes and Microchannel Plates
- Nuclear Physics and Applications
- History and Developments in Astronomy
- Ionosphere and magnetosphere dynamics
- Spacecraft and Cryogenic Technologies
- Superconducting Materials and Applications
Louisiana State University
2016-2025
Space Science Institute
2024-2025
University of Sheffield
2024
Indiana University Kokomo
2018
Space Telescope Science Institute
2008-2009
Kitt Peak National Observatory
2009
Lowell Observatory
2009
Maria Mitchell Association
2005-2007
University College London
2006
University of Manchester
2006
view Abstract Citations (9701) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Relationship between Infrared, Optical, and Ultraviolet Extinction Cardelli, Jason A. ; Clayton, Geoffrey C. Mathis, John S. parameterized extinction data of Fitzpatrick Massa (1986, 1988) for the ultraviolet various sources optical near-infrared are used to derive a meaningful average law over 3.5 micron 0.125 wavelength range which is applicable both diffuse...
We present an exhaustive, quantitative comparison of all the known extinction curves in Small and Large Magellanic Clouds (SMC LMC) with our understanding general behavior Milky Way curves. The R_V dependent CCM relationship sample used to derive this is describe ultraviolet portion SMC LMC are derived from archival IUE data, except for one new curve which was measured using HST/STIS observations. optical (for SMC) literature UBVRI photometry LMC). near-infrared calculated mainly 2MASS...
The large amount of dust produced by this supernova may help explain the observed in young galaxies.
The Legacy ExtraGalactic UV Survey (LEGUS) is a Cycle 21 Treasury program on the Hubble Space Telescope aimed at investigation of star formation and its relation with galactic environment in nearby galaxies, from scales individual stars to those ∼kiloparsec-size clustered structures. Five-band imaging near-ultraviolet I band Wide-Field Camera 3 (WFC3), plus parallel optical Advanced for Surveys (ACS), being collected selected pointings 50 galaxies within local 12 Mpc. filters used...
Dust extinction is one of the fundamental measurements dust grain sizes, compositions, and shapes. Most wavelength dependent variations seen in Milky Way are strongly correlated with single parameter R(V)=A(V)/E(B-V). Existing R(V) relationships use a mixture spectroscopic photometry observations, hence do not fully capture all important features nor continuum variations. Using four existing samples spectroscopically measured curves, we consistently measure relationship from far-ultraviolet...
This year marks the bicentennial of discovery variability R Coronae Borealis. The Borealis (RCB) stars are distinguished from other hydrogen-deficient objects by their spectacular dust formation episodes. They may decline up to 8 magnitudes in a few weeks revealing rich emission-line spectrum. Their atmospheres have unusual abundances with very little hydrogen and an overabundance carbon nitrogen. RCB thought be product final helium shell flash or coalescence binary white-dwarf system. Dust...
The recent discovery that the UV dust extinction in starburst galaxies is similar to found Small Magellanic Cloud (SMC) motivated us re-investigate ultraviolet (UV) SMC. We have been able improve significantly on previous studies by carefully choosing pairs of well matched reddened and unreddened stars. In addition, we benefited from improved S/N NEWSIPS IUE data larger sample SMC stars now available. Searching Final Archive, only four suitable early-type were had comparison for three these...
We present late-time optical and mid-infrared observations of the Type II supernova 2003gd in galaxy NGC 628. Mid-infrared excesses consistent with cooling dust ejecta are observed 499 to 678 days after outburst accompanied by increasing extinction growing asymmetries emission-line profiles. Radiative-transfer models show that up 0.02 solar masses has formed within ejecta, beginning as early 250 outburst. These formation can be efficient massive-star supernovae could have been major...
We present new Herschel photometric and spectroscopic observations of Supernova 1987A, carried out in 2012. Our dedicated measurements provide 70 micron data improved imaging quality at 100 160 compared to previous 2010. spectra show only weak CO line emission, an upper limit for the 63 [O I] flux, eliminating possibility that contaminations distort previously estimated dust mass. The far-infrared spectral energy distribution (SED) is well fitted by thermal emission from cold dust. newly...
We present an overview of the HERschel Inventory The Agents Galaxy Evolution (HERITAGE) in Magellanic Clouds project, which is a Herschel Space Observatory open time key program. mapped Large Cloud (LMC) and Small (SMC) at 100, 160, 250, 350, 500 μm with Spectral Photometric Imaging Receiver (SPIRE) Photodetector Array Camera Spectrometer (PACS) instruments on board using SPIRE/PACS parallel mode. overriding science goal HERITAGE to study life cycle matter as traced by dust LMC SMC....
The dust properties in the Large and Small Magellanic clouds (LMC/SMC) are studied using HERITAGE Herschel Key Project photometric data five bands from 100 to 500 μm. Three simple models of emission were fit observations: a single temperature blackbody modified by power-law emissivity (SMBB), broken (BEMBB), two blackbodies with different temperatures, both same (TTMBB). Using these models, we investigate origin submillimeter excess, defined as above that expected SMBB observations <200 We...
The Small Magellanic Cloud (SMC) provides a unique laboratory for the study of lifecycle dust given its low metallicity (~1/5 solar) and relative proximity (~60 kpc). This motivated SAGE-SMC (Surveying Agents Galaxy Evolution in Tidally-Stripped, Low Metallicity Cloud) Spitzer Legacy program with specific goals studying amount type present interstellar medium, sources winds evolved stars, how much is consumed star formation. mapped full SMC (30 sq. deg.) including Body, Wing, Tail 7 bands...
Supernova (SN) explosions are crucial engines driving the evolution of galaxies by shock heating gas, increasing metallicity, creating dust, and accelerating energetic particles. In 2012 we used Atacama Large Millimeter/Submillimeter Array to observe SN 1987A, one best-observed supernovae since invention telescope. We present spatially resolved images at 450um, 870um, 1.4mm, 2.8mm, an important transition wavelength range. Longer emission is dominated synchrotron radiation from...
We report the large effort which is producing comprehensive high-level young star cluster (YSC) catalogues for a significant fraction of galaxies observed with Legacy ExtraGalactic UV Survey (LEGUS) Hubble treasury program. present methodology developed to extract positions, verify their genuine nature, produce multiband photometry (from NUV NIR), and derive physical properties via spectral energy distribution fitting analyses. use nearby spiral galaxy NGC628 as test case demonstrating...
We estimate the total dust input from cool evolved stars in Small Magellanic Cloud (SMC), using 8 micron excess emission as a proxy for dust-production rate. find that Asymptotic Giant Branch (AGB) and red supergiant (RSG) produce (8.6-9.5) x 10^7 solar masses per year of dust, depending on fraction far-infrared sources belong to star population (with 10%-50% uncertainty individual rates). RSGs contribute least (<4%), while carbon-rich AGB (especially so-called "extreme" stars) account...
The spatial variations of the gas-to-dust ratio (GDR) provide constraints on chemical evolution and lifecycle dust in galaxies. We examine relation between gas at 10–50 pc resolution Large Small Magellanic Clouds (LMC SMC) based Herschel far-infrared (FIR), H i 21 cm, CO, Hα observations. In diffuse atomic interstellar medium (ISM), we derive GDR as slope dust–gas find GDRs 380 3 LMC, 1200 120 SMC, not including helium. atomic-to-molecular transition is located surface densities 0.05 M☉ pc−2...
Abstract We present initial results from a James Webb Space Telescope (JWST) survey of the youngest Galactic core-collapse supernova remnant, Cassiopeia A (Cas A), made up NIRCam and MIRI imaging mosaics that map emission main shell, interior, surrounding circumstellar/interstellar material (CSM/ISM). also four exploratory positions Medium Resolution Spectrograph integral field unit spectroscopy sample ejecta, CSM, associated dust representative shocked unshocked regions. Surprising...
Abstract The Small Magellanic Cloud (SMC) shows a large variation in ultraviolet (UV) dust extinction curves, ranging from Milky Way (MW) like to significantly steeper curves with no detectable 2175 Å bump. This result is based on sample of only nine sight lines. From Hubble Space Telescope Imaging Spectrograph and IUE spectra OB stars, we have measured UV along 32 SMC lines where eight these were published previously. We find 16 steep bump, four MW-like two fairly flat weak/absent bumps, 10...
We have reanalyzed the Large Magellanic Cloud's (LMC) ultraviolet (UV) extinction using data from IUE final archive. Our new analysis takes advantage of improved signal-to-noise ratio NEWSIPS reduction, exclusion stars with very low reddening, careful selection well-matched comparison stars, and an effects Galactic foreground dust. Differences between average curves 30 Dor region rest LMC are reduced compared previous studies. find that there is a group weak 2175 Å bumps lie in or near...
view Abstract Citations (191) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Determination of Ultraviolet Extinction from the Optical and Near-Infrared Cardelli, Jason A. ; Clayton, Geoffrey C. Mathis, John S. correlation optical-near-infrared photometry for a sample stars with well-determined ultraviolet extinction is examined. A good found; in particular, it found that value total-to-selective correlates well level linear UV background...
We have found that at least seven hydrogen-deficient carbon (HdC) and R Coronae Borealis (RCB) stars, 16O/18O ratios close to in some cases less than unity, values are orders of magnitude lower measured other stars (the Solar value is 500). Greatly enhanced 18O evident every HdC RCB we cool enough detectable CO bands. The three < 1, any the stars. These discoveries important clues determining evolutionary pathways for which two models been proposed: double degenerate (white dwarf (WD)...
The HERschel Inventory of Agents Galaxy Evolution (HERITAGE) the Magellanic Clouds will use dust emission to investigate life cycle matter in both Large and Small (LMC SMC). Using Herschel Space Observatory's PACS SPIRE photometry cameras, we imaged a 2x8 square degree strip through LMC, at position angle ~22.5 degrees as part science demonstration phase mission. We present data all 5 bands: 100 160 {\mu}m 250, 350 500 {\mu}m. two models that adequately fit spectral energy distribution for...
SN 2007od exhibits characteristics that have rarely been seen in a Type IIP supernova (SN). Optical V band photometry reveals very steep brightness decline between the plateau and nebular phases of ~4.5 mag, likely due to containing low mass 56Ni. The optical spectra show an evolution from normal with broad Halpha emission, complex, four component emission profile exhibiting asymmetries caused by dust extinction after day 232. This is similar spectral IIn 1998S, although no early-time narrow...
We present the star cluster catalogs for 17 dwarf and irregular galaxies in $HST$ Treasury Program "Legacy ExtraGalactic UV Survey" (LEGUS). Cluster identification photometry this subsample are similar to that of entire LEGUS sample, but special methods were developed provide robust with accurate fluxes due low statistics. The colors ages largely consistent two widely used aperture corrections, a significant fraction clusters more compact than average training cluster. However, ensemble...