Search Publications
Tracing the Origin of Moving Groups. I. The γ Leo Moving Group with High-resolution Spectra from the Subaru Telescope
Zhao, G.; Chen, Y. Q.; Zhao, J. K. +7 more
We present chemical abundances of 15 stars in the γ Leo moving group based on high-resolution spectra with the Subaru High Dispersion Spectrograph. The sample was picked up by applying wavelet transform to UVW velocity components of stars in the solar neighborhood. Both photometric and spectroscopic method have been used to determine the stellar p…
An Infrared Study of the Circumstellar Material Associated with the Carbon Star R Sculptoris
Lau, R. M.; Hankins, M. J.; Herter, T. L. +2 more
The asymptotic giant branch (AGB) star R Sculptoris (R Scl) is one of the most extensively studied stars on the AGB. R Scl is a carbon star with a massive circumstellar shell (M shell ∼ 7.3 × 10-3 M ⊙) that is thought to have been produced during a thermal pulse event ∼2200 years ago. To study the thermal dust emis…
Alumina Polymorphism in the Circumstellar Dust Shells of Asymptotic Giant Branch Stars
Sargent, Benjamin A.
Many emission features remain unidentified in the infrared spectra of asymptotic giant branch (AGB) stars. In particular, features at ∼11, 20, 28, and 32 µm have been noted in mid-infrared spectra of oxygen-rich AGB stars. Here, I present models of dust excess emission in 36 spectra of 24 AGB stars from the Short Wavelength Spectrometer on b…
Discovery of Redshifted He-like Iron Absorption Line from Luminous Accreting Neutron Star SMC X-1
Odaka, Hirokazu; Tamagawa, Toru; Nakano, Toshio +1 more
We have analyzed X-ray data of SMC X-1 obtained with Suzaku and discovered the combination of an absorption line and an underlying broadened emission line centered at 6.4 keV in an observation performed on 2012 May 19. This absorption line is centered at {6.61}-0.03+0.02 {keV} with an absorption strength of {5.9}-1.4
The Carnegie-Chicago Hubble Program: Calibration of the Near-infrared RR Lyrae Period-Luminosity Relation with HST
Kollmeier, Juna A.; Madore, Barry F.; Freedman, Wendy L. +12 more
We present photometry of 30 Galactic RR Lyrae variables taken with HST WFC3/IR for the Carnegie-Chicago Hubble Program. These measurements form the base of the distance-ladder measurements that comprise a pure Population II base to a measurement of H o at an accuracy of 3%. These data are taken with the same instrument and filter (F16…
Gemini, SOFIA, and ATCA Reveal Very Young, Massive Protostars in the Collapsing Molecular Cloud BYF 73
Ryder, Stuart D.; Li, Dan; Pitts, Rebecca L. +1 more
We present multi-wavelength data on the globally infalling molecular cloud/protostellar cluster BYF 73. These include new far-infrared (FIR) spectral line and continuum data from the Stratospheric Observatory for Infrared Astronomy’s (SOFIA’s) Far Infrared Field-Imaging Line Spectrometer (FIFI-LS), mid-infrared (MIR) observations with the Thermal-…
A Study of Low-mass X-Ray Binaries in the Low-luminosity Regime
Sonbas, E.; Dhuga, K. S.; Göğüş, E.
A recent study of a small sample of X-ray binaries (XRBs) suggests a significant softening of spectra of neutron star (NS) binaries as compared to black hole (BH) binaries in the luminosity range 1034-1037 erg s-1. This softening is quantified as an anticorrelation between the spectral index and the 0.5-10 keV X-ra…
Spectroscopic Observations of the Outflowing Wind in the Lensed Quasar SDSS J1001+5027
Charlton, Jane C.; Eracleous, Michael; Oguri, Masamune +4 more
We performed spectroscopic observations of the small-separation lensed quasar SDSS J1001+5027, whose images have an angular separation θ =2\buildrel{\prime\prime}\over{.} 86, and placed constraints on the physical properties of gas clouds in the vicinity of the quasar (i.e., in the outflowing wind launched from the accretion disk). The two cylinde…
A New Method to Comprehensively Diagnose Shock Waves in the Solar Atmosphere Based on Simultaneous Spectroscopic and Imaging Observations
He, Jiansen; Wang, Linghua; Yan, Limei +3 more
Shock waves are believed to play an important role in plasma heating. The shock-like temporal jumps in radiation intensity and Doppler shift have been identified in the solar atmosphere. However, a quantitative diagnosis of the shocks in the solar atmosphere is still lacking, seriously hindering the understanding of shock dissipative heating of th…
Thermal Emission in the Quiescent Neutron Star SAX J1810.8-2609
Allen, Jessamyn L.; Homan, Jeroen; Chakrabarty, Deepto +1 more
We have observed the neutron star low-mass X-ray binary SAX J1810.8-2609 in quiescence with XMM-Newton. SAX J1810.8-2609 is one of the faintest non-pulsing neutron star low-mass X-ray binaries in quiescence and previously only had upper limits on its quiescent thermal emission. We found SAX J1810.8-2609 at the same 0.5-10 keV, unabsorbed luminosit…