Search Publications
Linear: A Novel Algorithm for Reconstructing Slitless Spectroscopy from HST/WFC3
Casertano, S.; Ryan, R. E., Jr.; Pirzkal, N.
We present a grism extraction package (LINEAR) designed to reconstruct 1D spectra from a collection of slitless spectroscopic images, ideally taken at a variety of orientations, dispersion directions, and/or dither positions. Our approach is to enumerate every transformation between all direct image positions (i.e., a potential source) and the col…
iPTF Survey for Cool Transients
Fox, O. D.; Cenko, S. B.; Sollerman, J. +25 more
We performed a wide-area (2000 deg2) g and I band experiment as part of a two month extension to the Intermediate Palomar Transient Factory. We discovered 36 extragalactic transients including iPTF17lf, a highly reddened local SN Ia, iPTF17bkj, a new member of the rare class of transitional Ibn/IIn supernovae, and iPTF17be, a candidate …
Near-infrared Spectra of a Sample of Galactic Unclassified B[e] Stars
Kraus, Michaela; Arias, María L.; Cidale, Lydia S. +4 more
B[e] stars are surrounded by cool and dense circumstellar environments where molecules and dust are formed. These stars are rare and display complex spectra whose photospheric features are frequently veiled by their circumstellar envelopes, making it difficult to assign them spectral types and evolutionary phases. On the basis of a detailed analys…
Physical Nature and Orbital Behavior of the Eclipsing System UZ Leonis
Lee, Jae Woo; Park, Jang-Ho
New CCD photometric observations of UZ Leo were obtained between 2012 February and 2013 April, and on 2017 February. Its physical properties were derived from detailed analyses of our light curves and existing radial velocities. The results indicate that this system is a totally eclipsing A-subtype overcontact binary with both a high fill-out fact…
Complete IRAC Mapping of the CFHTLS-DEEP, MUSYC, and NMBS-II Fields
Muzzin, Adam; van Dokkum, Pieter; Bezanson, Rachel +19 more
The IRAC mapping of the NMBS-II fields program is an imaging survey at 3.6 and 4.5 µm with the Spitzer Infrared Array Camera (IRAC). The observations cover three Canada-France-Hawaii Telescope Legacy Survey Deep (CFHTLS-D) fields, including one also imaged by AEGIS, and two MUSYC fields. These are then combined with archival data from all pr…
Is the Cometary Nucleus-extraction Technique Reliable?
Li, Jian-Yang; Hui, Man-To
We investigated the reliability of the cometary nucleus-extraction technique, and found the answer to this question: it depends. Our experiment reveals that, given an optically thin coma, generally, the smaller the signal ratio of nucleus to coma, the less reliable the cometary nucleus-extraction technique is. We strongly suggest the technique onl…
ProtoDESI: First On-Sky Technology Demonstration for the Dark Energy Spectroscopic Instrument
Serrano, Santiago; Weaver, Benjamin A.; Dey, Arjun +38 more
The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the universe using the baryon acoustic oscillations technique. The spectra of 35 million galaxies and quasars over 14,000 square degrees will be measured during a 5-year survey. A new prime focus corrector for the Mayall telescope at Kitt Peak…
Spectroastrometric Study of Ro-vibrational CO Emission from the Herbig Ae Star HD 179218 with ISHELL on the NASA Infrared Telescope Facility
Najita, Joan R.; Brittain, Sean D.; Carr, John S.
We present analysis of commissioning M-band data acquired with the infrared echelle spectrograph (iSHELL) on NASA’s Infrared Telescope Facility. In this paper we describe the delivered performance of the instrument for these M-band observations and the data reduction process. The feasibility of using iSHELL for spectro-astrometry is tested on the …
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…
The Milky Way Rotation Curve Revisited
Krełowski, J.; Strobel, A.; Galazutdinov, G.
The paper revisits the problem described in detail in our Paper I (Galazutdinov et al.) concluding that the rotation curve of the thin gaseous Galactic disk, represented by the CaII lines, is Keplerian outside the solar orbit rather than flat. Now we apply new trigonometric Gaia parallaxes, published in the Data Release 2. We demonstrate that the …