Search Publications
Hitomi observations of the LMC SNR N 132 D: Highly redshifted X-ray emission from iron ejecta
Done, Chris; Safi-Harb, Samar; Hamaguchi, Kenji +191 more
We present Hitomi observations of N 132 D, a young, X-ray bright, O-rich core-collapse supernova remnant in the Large Magellanic Cloud (LMC). Despite a very short observation of only 3.7 ks, the Soft X-ray Spectrometer (SXS) easily detects the line complexes of highly ionized S K and Fe K with 16-17 counts in each. The Fe feature is measured for t…
Star formation quenching in green valley galaxies at 0.5 ≲ z ≲ 1.0 and constraints with galaxy morphologies
Menéndez-Delmestre, K.; Sheth, K.; Gonçalves, T. S. +1 more
We calculate the star formation quenching time-scales in green valley galaxies at intermediate redshifts (z ∼ 0.5-1) using stacked zCOSMOS spectra of different galaxy morphological types: spheroidal, disc-like, irregular and merger, dividing disc-like galaxies further into unbarred, weakly barred and strongly barred, assuming a simple exponentiall…
Evidence against Anomalous Compositions for Giants in the Galactic Nuclear Star Cluster
Schultheis, M.; Ryde, N.; Rich, R. M. +5 more
Very strong Sc I lines have recently been found in cool M giants in the Nuclear Star Cluster (NSC) in the Galactic center. Interpreting these as anomalously high scandium abundances in the Galactic center would imply a unique enhancement signature and chemical evolution history for NSCs, and a potential test for models of chemical enrichment in th…
Ground calibration of the Astro-H (Hitomi) soft x-ray spectrometer
Tsujimoto, Masahiro; Eckart, Megan E.; Hoshino, Akio +25 more
The Astro-H (Hitomi) Soft X-ray Spectrometer (SXS) was a pioneering imaging x-ray spectrometer with 5 eV energy resolution at 6 keV. The instrument used a microcalorimeter array at the focus of a high-throughput soft x-ray telescope to enable high-resolution nondispersive spectroscopy in the soft x-ray waveband (0.3 to 12 keV). We present the suit…
Fluctuations of the gravitational field generated by a random population of extended substructures
Peñarrubia, Jorge
A large population of extended substructures generates a stochastic gravitational field that is fully specified by the function p(F), which defines the probability that a tracer particle experiences a force F within the interval F, F+d{F}. This paper presents a statistical technique for deriving the spectrum of random fluctuations directly from th…
Do cosmological data rule out f (R ) with w ≠-1 ?
Battye, Richard A.; Pace, Francesco; Bolliet, Boris
We review the equation of state (EoS) approach to dark sector perturbations and apply it to f (R ) gravity models of dark energy. We show that the EoS approach is numerically stable and use it to set observational constraints on designer models. Within the EoS approach we build an analytical understanding of the dynamics of cosmological perturbati…
Multiple Stellar Populations of Globular Clusters from Homogeneous Ca-CN Photometry. III. NGC 6752
Lee, Jae-Woo
We present a multiple stellar population study of the globular cluster NGC 6752. We show that our new photometric CN index accurately traces the CN and the nitrogen abundances in cool giants, finding the discrete double red giant branch (RGB) and asymptotic giant branch (AGB) sequences with number ratios between the CN-weak and the CN-strong popul…
H2CO Ortho-to-para Ratio in the Protoplanetary Disk HD 163296
Öberg, K. I.; Carpenter, J.; Qi, C. +3 more
Ortho-to-para (o/p) ratios of species like water, ammonia, and formaldehyde ({{{H}}}2{CO}) are believed to encode information about the formation history of the molecule. Measurements of o/p ratios in protoplanetary disks could thus be used to constrain their physical and chemical histories. We present the first measurement of the {{{H}…
Broad-band spectral study of the jet-disc emission in the radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342
Dewangan, Gulab C.; Raychaudhuri, Biplab; Mallick, Labani +1 more
We present a broad-band spectral study of the radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342 based on multi-epoch observations performed with Nuclear Spectroscopic Telescope Array on 2014 March 15, and two simultaneous observations performed with Suzaku and Swift on 2009 July 26 and 2013 March 1. We found the presence of a strong soft X-ray e…
Quantifying widespread aqueous surface weathering on Mars: The plateaus south of Coprates Chasma
Quantin-Nataf, C.; Millot, C.; Flahaut, J. +4 more
Pedogenesis has been previously proposed on the plateaus around Coprates Chasma, Valles Marineris to explain the presence of widespread clay sequences with Al-clays and possible hydrated silica over Fe/Mg-clays on the surface of the plateaus (Le Deit et al., 2012; Carter et al., 2015). We use previous observations together with new MRO targeted ob…