Search Publications
A far-UV survey of three hot, metal-polluted white dwarf stars: WD0455-282, WD0621-376, and WD2211-495
Webb, John K.; Lee, Chung-Chi; Reindl, Nicole +7 more
Using newly obtained high-resolution data (R ∼ 1 × 105) from the Hubble Space Telescope, and archival UV data from the Far Ultraviolet Spectroscopic Explorer, we have conducted a detailed UV survey of the three hot, metal-polluted white dwarfs WD0455-282, WD0621-376, and WD2211-495. Using bespoke model atmospheres, we measured Teff…
An investigation of C, N, and Na abundances in red giant stars of the Sculptor dwarf spheroidal galaxy
Da Costa, G. S.; Yong, D.; Norris, J. E. +1 more
The origin of the star-to-star abundance variations found for the light elements in Galactic globular clusters (GGCs) is not well understood, which is a significant problem for stellar astrophysics. While the light element abundance variations are very common in globular clusters, they are comparatively rare in the Galactic halo field population. …
The nature of the infrared counterpart and of the optical nebula associated with the Central Compact Object in Vela Jr.
Pellizzoni, A.; De Luca, A.; Mignani, R. P. +3 more
The X-ray source CXO J085201.4-461753 in the few kyr-old Vela Jr. supernova remnant (SNR, G266.2-1.2) belongs to the peculiar class of isolated neutron stars dubbed `Central Compact Objects' (CCOs). At variance with the other CCOs, which are only detected in the X-rays, CXO J085201.4-461753 has been possibly detected also at other wavelengths. In …
Slow decline and rise of the broad [O III] emission line in globular cluster black hole candidate RZ2109
Kundu, Arunav; Strader, Jay; Dage, Kristen C. +6 more
RZ2109 is the first of several extragalactic globular clusters shown to host an ultraluminous X-ray source. RZ2109 is particularly notable because optical spectroscopy shows it has broad, luminous [O III] λλ4959,5007 emission, while also having no detectable hydrogen emission. The X-ray and optical characteristics of the source in RZ2109 make it a…
A gas-phase primordial origin of O2 in comet 67P/Churyumov-Gerasimenko
Williams, D. A.; Wilson, T. G.; Rawlings, J. M. C.
Recent observations made by the Rosetta/ROSINA instrument have detected molecular oxygen in the coma of comet 67P/Churyumov-Gerasimenko with abundances at the 1-10 per cent level relative to H2O. Previous studies have indicated that the likely origin of the O2 may be surface chemistry of primordial (dark cloud) origin, requir…
A multiwavelength study of the debris disc around 49 Cet
Henning, Thomas; Lee, Eve J.; Boccaletti, Anthony +17 more
In a multiwavelength study of thermal emission and scattered light images we analyse the dust properties and structure of the debris disc around the A1-type main-sequence star 49 Cet. As a basis for this study, we present new scattered light images of the debris disc known to possess a high amount of both dust and gas. The outer region of the disc…
Metallicity estimates of young clusters in the Magellanic Clouds from Strömgren photometry of supergiant stars
Piatti, Andrés E.; Pietrzyński, Grzegorz; Graczyk, Dariusz +2 more
We present results obtained from Strömgren photometry of 13 young (∼30-220 Myr) Magellanic Cloud (MC) clusters, most of them lacking in the literature from direct metallicity measurements. We derived for them [Fe/H] values from a high-dispersion spectroscopy-based empirical calibration of the Strömgren metallicity sensitive index m1 for…
Probing the unidentified Fermi blazar-like population using optical polarization and machine learning
Blinov, D.; Liodakis, I.
The Fermi γ-ray space telescope has revolutionized our view of the γ-ray sky and the high-energy processes in the Universe. While the number of known γ-ray emitters has increased by orders of magnitude since the launch of Fermi, there is an ever increasing number of, now more than a thousand, detected point sources whose low-energy counterpart is …
Detection of metal-rich, cool-warm gas in the outskirts of galaxy clusters
Charlton, Jane C.; Nagai, Daisuke; Pradeep, Jayadev +3 more
We present an ultraviolet quasar absorption line analysis of metal lines associated with three strong intervening H I absorbers (with N(H I) > 1016.5 cm-2) detected in the outskirts of Sunyaev-Zel'dovich (SZ) effect-selected galaxy clusters (zcl ∼ 0.4-0.5), within clustocentric impact parameters of ρcl
A universal relation of dust obscuration across cosmic time
Zheng, Xian Zhong; Wuyts, Stijn; Pan, Zhizheng +2 more
We investigate dust obscuration as parametrized by the infrared excess IRX ≡ LIR/LUV in relation to global galaxy properties, using a sample of ∼32 000 local star-forming galaxies (SFGs) selected from SDSS (Sloan Digital Sky Survey), GALEX (Galaxy Evolution Explorer), and WISE (Wide-field Infrared Survey Explorer). We show th…