Search Publications
The Cluster Population of the Irregular Galaxy NGC 4449 as Seen by the Hubble Advanced Camera for Surveys
Tosi, M.; van der Marel, R. P.; Aloisi, A. +1 more
We present a study of the star cluster population in the starburst irregular galaxy NGC 4449 based on B, V, I, and Hα images taken with the Advanced Camera for Surveys on the Hubble Space Telescope. We derive cluster properties such as size, ellipticity, and total magnitude. Cluster ages and masses are derived fitting the observed spectral energy …
A New Census of the Variable Star Population in the Globular Cluster NGC 2419
Di Criscienzo, M.; Clementini, G.; Ripepi, V. +6 more
We present B, V, and I CCD light curves for 101 variable stars belonging to the globular cluster NGC 2419, 60 of which are new discoveries, based on data sets obtained at the Telescopio Nazionale Galileo, the Subaru telescope, and the Hubble Space Telescope. The sample includes 75 RR Lyrae stars (38 RRab, 36 RRc, and one RRd), one Population II Ce…
Identification of a Wide, Low-Mass Multiple System Containing the Brown Dwarf 2MASS J0850359+105716
Burgasser, Adam J.; Faherty, Jacqueline K.; Bochanski, John J. +3 more
We report our discovery of NLTT 20346 as an M5+M6 companion system to the tight binary (or triple) L dwarf 2MASS J0850359+105716. This nearby (~31 pc), widely separated (~7700 AU) quadruple system was identified through a cross-match of proper motion catalogs. Follow-up imaging and spectroscopy of NLTT 20346 revealed it to be a magnetically active…
Present-day Mass Function of Six Small Magellanic Cloud Intermediate-age and Old Star Clusters
Grebel, Eva K.; Gallagher, John S., III; Sabbi, Elena +8 more
We determined the present-day mass functions (PDMFs) of the five intermediate-age star clusters Lindsay 1, Kron 3, NGC 339, NGC 416, and Lindsay 38 and the old star cluster NGC 121 in the Small Magellanic Cloud (SMC) based on observations with the Hubble Space Telescope Advanced Camera for Surveys. The global PDMFs are well matched by Salpeter-lik…
Determining Interstellar Carbon Abundances from Strong-line Transitions
Murthy, J.; Babu, B. R. S.; Parvathi, V. S. +1 more
Carbon is arguably the most important element in the interstellar medium, yet its abundance in gas and dust is poorly understood due to a paucity of data. We explore the possibility of substantially increasing our knowledge of interstellar carbon by applying and assessing a new method for determining the column density of the dominant ion of inter…
The Widest-separation Substellar Companion Candidate to a Binary T Tauri Star
Kuzuhara, M.; Tamura, M.; Ishii, M. +3 more
The results of near-infrared imaging and spectroscopy of a substellar companion (SR12 C), with a possible planetary mass, of a binary T Tauri star (SR12 AB) in the ρ Ophiuchi star-forming region are presented. The object is separated by ~8farcs7, corresponding to ~1100 AU at 125 pc, and has an H-band brightness of 15.2 mag and infrared spectra sug…
Star Clusters as Tracers of Interactions in Stephan's Quintet (Hickson Compact Group 92)
Bastian, N.; Konstantopoulos, I. S.; Gallagher, S. C. +5 more
Stephan's Quintet (SQ; also known as Hickson Compact Group 92) is a compact group of galaxies that exhibits numerous signs of interactions between its members. Using high-resolution (0farcs04 per pixel) images of SQ in B 438, V 606, and I 814 bands from the Early Release Science project obtained with the Wide Field…
Four New T Dwarfs Identified in Pan-STARRS 1 Commissioning Data
Price, P. A.; Magnier, Eugene A.; Goldman, Bertrand +14 more
A complete well-defined sample of ultracool dwarfs is one of the key science programs of the Pan-STARRS 1 optical survey telescope (PS1). Here we combine PS1 commissioning data with the Two Micron All Sky Survey (2MASS) to conduct a proper motion search (0farcs1-2farcs0 yr-1) for nearby T dwarfs, using optical+near-IR colors to select o…
Spitzer 24 µm Survey for Dust Disks around Hot White Dwarfs
Volk, Kevin; Rauch, Thomas; De Marco, Orsola +6 more
Two types of dust disks around white dwarfs (WDs) have been reported: small dust disks around cool metal-rich WDs consisting of tidally disrupted asteroids and a large dust disk around the hot central WD of the Helix planetary nebula (PN) possibly produced by collisions among Kuiper-Belt-like objects. To search for more dust disks of the latter ty…
History and Modes of Star Formation in the Most Active Region of the Small Magellanic Cloud, NGC 346
Cignoni, M.; Tosi, M.; Sabbi, E. +2 more
We discuss the star formation history of the Small Magellanic Cloud (SMC) region NGC 346 based on Hubble Space Telescope images. The region contains both field stars and cluster members. Using a classical synthetic color-magnitude diagram (CMD) procedure applied to the field around NGC 346 we find that the star formation pace there has been rising…