Search Publications
Possible substellar companions in low-mass eclipsing binaries: GU Bootis and YY Geminorum
Wolf, M.; Mašek, M.; Kučáková, H. +10 more
We present the next results of our long-term observational project to analyze the variations in the orbital periods of low-mass eclipsing binaries. About 70 new precise mid-eclipse times recorded with a CCD were obtained for two eclipsing binaries with short orbital periods: GU Boo (P = 0.d49) and YY Gem (0.d81). Observed-m…
Delayed Stellar Mass Assembly in the Low Surface Brightness Dwarf Galaxy KDG 215
McQuinn, Kristen B. W.; Cannon, John M.; Dolphin, Andrew E. +17 more
We present H I spectral line and optical broadband images of the nearby low surface brightness dwarf galaxy KDG 215. The H I images, acquired with the Karl G. Jansky Very Large Array, reveal a dispersion-dominated interstellar medium with only weak signatures of coherent rotation. The H I gas reaches a peak mass surface density of 6 M ⊙…
A 2 R ⊕ Planet Orbiting the Bright Nearby K Dwarf Wolf 503
Henning, Thomas; Latham, David W.; Schlieder, Joshua E. +21 more
Since its launch in 2009, the Kepler telescope has found thousands of planets with radii between that of Earth and Neptune. Recent studies of the distribution of these planets have revealed a gap in the population near 1.5-2.0 R ⊕, informally dividing these planets into “super-Earths” and “sub-Neptunes.” The origin of this division is d…
2MASS J11151597+1937266: A Young, Dusty, Isolated, Planetary-mass Object with a Potential Wide Stellar Companion
Burgasser, Adam J.; Gagné, Jonathan; Bardalez Gagliuffi, Daniella C. +4 more
We present 2MASS J11151597+1937266, a recently identified low-surface-gravity L dwarf, classified as an L2γ based on Sloan Digital Sky Survey optical spectroscopy. We confirm this spectral type with near-infrared spectroscopy, which provides further evidence that 2MASS J11151597+1937266 is a low-surface-gravity L dwarf. This object also shows sign…
M31 PAndromeda Cepheid Sample Observed in Four HST Bands
Bender, Ralf; Seitz, Stella; Hopp, Ulrich +5 more
Using the M31 PAndromeda Cepheid sample and the HST PHAT data, we obtain the largest Cepheid sample in M31 with HST data in four bands. For our analysis we consider three samples: a very homogeneous sample of Cepheids based on the PAndromeda data, the mean magnitude corrected PAndromeda sample and a sample complementing the PAndromeda sample with …
NOEMA Observations of a Molecular Cloud in the Low-metallicity Galaxy Kiso 5639
Elmegreen, Bruce G.; Rubio, Monica; Muñoz-Tuñón, Casiana +4 more
A giant star-forming region in a metal-poor dwarf galaxy has been observed in optical lines with the 10 m Gran Telescopio Canarias (GTC) and in the emission line of CO(1-0) with the Northern Extended Millimeter Array (NOEMA) mm-wave interferometer. The metallicity was determined to be 12+{log}({{O}}/{{H}})=7.83+/- 0.09, from which we estimate a co…
Optical and UV surface brightness of translucent dark nebulae. Dust albedo, radiation field, and fluorescence emission by H2
Leinert, Ch.; Haas, M.; Väisänen, P. +4 more
Context. Dark nebulae display a surface brightness because dust grains scatter light of the general interstellar radiation field (ISRF). High-galactic-latitudes dark nebulae are seen as bright nebulae when surrounded by transparent areas which have less scattered light from the general galactic dust layer.
Aims: Photometry of the bright dark …
Link between the VLBI and Gaia Reference Frames
Liu, N.; Zhu, Z.; Liu, J. -C.
The link between the International Celestial Reference Frame at radio wavelength and the forthcoming Gaia optical reference frame is a mandatory task after the completion of the Gaia mission. Starting from the provisional reference frame in which Gaia astrometric solutions were obtained, we discuss the ways to correct the residual rotation and acc…
A Binary Offset Effect in CCD Readout and Its Impact on Astronomical Data
Aldering, G.; Perlmutter, S.; Gangler, E. +5 more
We have discovered an anomalous behavior of CCD readout electronics that affects their use in many astronomical applications. An offset in the digitization of the CCD output voltage that depends on the binary encoding of one pixel is added to pixels that are read out one, two, and/or three pixels later. One result of this effect is the introductio…
Testing stellar proper motions of TGAS stars using data from the HSOY, UCAC5 and PMA catalogues
Akhmetov, V. S.; Fedorov, P. N.; Velichko, A. B.
We analyse the stellar proper motions from the Tycho-Gaia Astrometric Solution (TGAS) and those from the ground-based HSOY, UCAC5 and PMA catalogues derived by combining them with Gaia DR1 space data. Assuming that systematic differences in stellar proper motions of the two catalogues are caused by a mutual rigid-body rotation of the reference cat…