Crotts, Arlin P. S., Hummels, Cameron
We follow Paper I with predictions of how gas leaking through the lunar surface could influence the regolith, as might be observed via optical Transient Lunar Phenomena (TLPs) and related effects. We...
The chemical compositions of 10 new sub-DLAs and strong Lyman-limit systems at z < 1.5 (2007)
Meiring, Joseph D., Kulkarni, Varsha P., Lauroesch, James T., Peroux, Celine, Khare, Pushpa, York, Donald G., ...
We present chemical abundance measurements from medium resolution observations of 8 sub-damped Lyman-alpha absorber and 2 strong Lyman-limit systems at z < 1.5 observed with the MIKE spectrograph on...
Metal Absorption Systems in Spectra of Pairs of QSOs (2007)
Tytler, David, Gleed, Mark, Melis, Carl, Chapman, Angela, Kirkman, David, Lubin, Dan, ...
We present the first large sample of absorption systems in paired QSOs consisting of 691 absorption systems in the spectra of 310 QSOs including 170 pairings. All these absorption systems have metal...
In Papers II and III we show that Transient Lunar Phenomena (TLPs) are likely related to lunar outgassing, albeit in ways not fully understood. Here we propose a path forward, in which current and...
Transient Lunar Phenomena: Regularity and Reality (2007)
Transient lunar phenomena (TLPs) have been reported for centuries, but their nature is largely unsettled. A review of TLP reports shows regularities in the observations; a key question is whether...
Lunar Outgassing, Transient Phenomena and The Return to The Moon, I: Existing Data (2007)
Herein the transient lunar phenomena (TLP) report database is subjected to a discriminating statistical filter robust against sites of spurious reports, and produces a restricted sample that may be...
Crotts, Arlin P. S., Hummels, Cameron
We consider the implications from Paper I on how gas leaking through the lunar surface might interact with the regolith, and in what respects this might affect or cause the appearance of optical...
New abundance determinations in z < 1.5 QSO absorbers: seven sub-DLAs and one DLA (2007)
Meiring, Joseph D., Lauroesch, James T., Kulkarni, Varsha P., Peroux, Celine, Khare, Pushpa, York, Donald G., ...
We present chemical abundance measurements from high resolution observations of 7 sub-damped Lyman-alpha absorbers and 1 damped Lyman-alpha system at z
Elemental Abundance Measurements in Low-redshift Damped Lyman Alpha Absorbers (2006)
Meiring, Joseph D., Kulkarni, Varsha P., Khare, Pushpa, Bechtold, Jill, York, Donald G., Cui, Jun, ...
We present elemental abundance measurements for 9 damped Ly-alpha systems (DLAs) and 1 sub-DLA at 0.1 < z < 1.5 from recent observations with the Multiple Mirror Telescope. Most of these absorbers...
Evolution of the Reverse Shock Emission from SNR 1987A (2006)
Heng, Kevin, McCray, Richard, Zhekov, Svetozar A., Challis, Peter M., Chevalier, Roger A., Crotts, Arlin P. S., ...
We present new (2004 July) G750L and G140L Space Telescope Imaging Spectrograph (STIS) data of the H-alpha and Ly-alpha emission from supernova remnant (SNR) 1987A. With the aid of earlier data, from...
Average Extinction Curves and Relative Abundances for QSO Absorption Line Systems at 1 (2006)
York, Donald G., Khare, Pushpa, Berk, Daniel Vanden, Kulkarni, Varsha P., Crotts, Arlin P. S., Lauroesch, James T., ...
We have studied a sample of 809 Mg II absorption systems with 1.0 < z_abs < 1.86 in the spectra of SDSS QSOs, with the aim of understanding the nature and abundance of the dust and the chemical...
Photometric Identification of Type Ia Supernovae at Moderate Redshift (2005)
Johnson, Benjamin D., Crotts, Arlin P. S.
Large photometric surveys with the aim of identifying many Type Ia supernovae (SNe) at moderate redshift are challenged in separating these SNe from other SN types. We are motivated to identify Type...
MACHOs in M31? Absence of evidence but not evidence of absence (2005)
Widrow, Lawrence M., Cseresnjes, Patrick, Kuijken, Konrad, Crotts, Arlin P. S., Bergier, Alexander, ...
We present results of a microlensing survey toward the Andromeda Galaxy (M31) carried out during four observing seasons at the Isaac Newton Telescope (INT). This survey is part of the larger...
HST Imaging of MEGA Microlensing Candidates in M31 (2005)
Cseresnjes, Patrick, Crotts, Arlin P. S., Bergier, Alex, Baltz, Edward A., Gyuk, Geza, ...
We investigate $HST$/ACS and WFPC2 images at the positions of five candidate microlensing events from a large survey of variability in M31 (MEGA). Three closely match unresolved sources, and two...
The Three-Dimensional Circumstellar Environment of SN 1987A (2005)
Sugerman, Ben E. K., Crotts, Arlin P. S., Kunkel, William E., Heathcote, Stephen R., Lawrence, Stephen S.
We present the detailed construction and analysis of the most complete map to date of the circumstellar environment around SN 1987A, using ground and space-based imaging from the past 16 years....
A New View of the Circumstellar Environment of SN 1987A (2005)
Sugerman, Ben E. K., Crotts, Arlin P. S., Kunkel, William E., Heathcote, Stephen R., Lawrence, Stephen S.
We summarize the analysis of a uniform set of both previously-known and newly-discovered scattered-light echoes, detected within 30" of SN 1987A in ten years of optical imaging, and with which we...
Metals and Dust in Intermediate-redshift Damped Ly-alpha Galaxies (2004)
Khare, Pushpa, Kulkarni, Varsha P., Lauroesch, James T., York, Donald G., Crotts, Arlin P. S., Nakamura, Osamu
We report spectroscopic observations with the Multiple Mirror Telescope for 11 damped Lyman-alpha absorbers (DLAs) or strong DLA candidates at 0.1 < z < 1.5, including several absorbers discovered in...
Evidence of Halo Microlensing in M31 (2004)
Uglesich, Robert R., Crotts, Arlin P. S., Baltz, Edward A., Boyle, Richard P., Corbally, Christopher J.
We report results from intensive monitoring of two fields on either side of M31,emphasizing microlensing involving stars and masses in M31. These results stem from the three-year VATT/Columbia survey...
Towards Constraints on Dark Energy from Absorption Spectra of Close Quasar Pairs (2003)
Lidz, Adam, Hui, Lam, Crotts, Arlin P. S., Zaldarriaga, Matias
A comparison between the line of sight power spectrum of absorption in the Lyman-alpha forest and the cross power spectrum between the absorption in neighboring lines of sight offers an...
First Microlensing Events From The MEGA Survey Of M31 (2003)
Kuijken, Konrad H., Crotts, Arlin P. S., Sackett, Penny D., Sutherland, Will J., Uglesich, Robert R., ...
We present the first M31 candidate microlensing events from the Microlensing Exploration of the Galaxy and Andromeda (MEGA) survey. MEGA uses several telescopes to detect microlensing towards the...
Multiple Light Echoes from Supernova 1993J (2002)
Sugerman, Ben E. K., Crotts, Arlin P. S.
Using the technique of PSF-matched image subtraction, we have analyzed archival HST/WFPC2 data to reveal details of at least two light-echo structures, including some unknown before now, around SN...
Evolution and Geometry of Hot Spots in Supernova Remnant 1987A (2002)
Sugerman, Ben E. K., Lawrence, Stephen S., Crotts, Arlin P. S., Bouchet, Patrice, Heathcote, Steve R.
We present ground-based near-infrared imaging and {\em HST} optical imaging and spectroscopy of the interaction between the ejecta of SN 1987A and its equatorial circumstellar ring. This interaction...
QSOs and Absorption Line Systems Surrounding the Hubble Deep Field (2000)
Berk, Daniel E. Vanden, Stoughton, Chris, Crotts, Arlin P. S., Tytler, David, Kirkman, David
We have imaged a 45x45 sq. arcmin. area centered on the Hubble Deep Field (HDF) in UBVRI passbands, down to respective limiting magnitudes of approximately 21.5, 22.5, 22.2, 22.2, and 21.2. The...
The Structure of the Circumstellar Envelope of SN 1987A (1999)
The volume around the SN 1987A contains a variety of structures, not just the three rings glowing in recombination lines. Many of these are revealed by light echoes, so are mapped in three dimensions...
SN 1987A's Circumstellar Envelope, II: Kinematics of the Three Rings and the Diffuse Nebula (1999)
Crotts, Arlin P. S., Heathcote, Stephen R.
We present several different measurements of the velocities of structures within the circumstellar envelope of SN 1987A, including the inner, equatorial ring (ER), outer rings (ORs), and the diffuse...
Optical Light Curves of the Type Ia Supernovae 1990N and 1991T (1997)
Lira, P., Suntzeff, Nicholas B., Phillips, M. M., Hamuy, Mario, Maza, Jose, Schommer, R. A., ...
We present UBVRI light curves for the bright Type Ia supernovae SN 1990N in NGC 4639 and SN 1991T in NGC 4527 based on photometry gathered in the course of the Calan/Tololo supernova program. Both...
Results from a Survey of Gravitational Microlensing towards M31 (1996)
Crotts, Arlin P. S., Tomaney, Austin B.
We describe the results of a search for microlensing events affecting stars in the outer bulge and inner disk of M31, due both to masses in M31 and the Galaxy. These observations, from 1994 and 1995...
Expanding the Realm of Microlensing Surveys with Difference Image Photometry (1996)
Tomaney, Austin B., Crotts, Arlin P. S.
We present a new technique for monitoring microlensing activity even in highly crowded fields, and use this technique to place limits on low-mass MACHOs in the haloes of M31 and the Galaxy. Unlike...
VATT/Columbia Microlensing Survey of M31 and the Galaxy (1996)
We describe the results and outline the methods used in a search for microlensing events affecting stars in the outer bulge and inner disk of M31, due both to masses in M31 and the Galaxy. These...
The Size and Nature of Lyman alpha Forest Clouds Probed by QSO Pairs and Groups (1995)
Fang, Yihu, Duncan, Robert C., Crotts, Arlin P. S., Bechtold, Jill
We describe a robust Bayesian statistical method for determining Lyman alpha forest cloud sizes in spherical and in thin disk geometries, using absorption in adjacent sightlines toward closely...
Bechtold, Jill, Crotts, Arlin P. S., Duncan, Robert C., Fang, Yihu
We have obtained spectroscopy of Q 1343+266 AB, a pair of quasars at redshift z = 2.03 with a projected separation of 9.5 arcseconds. This system is well-suited for probing the Ly-alpha forest, since...
Crotts, Arlin P. S., Bechtold, Jill, Fang, Yihu, Duncan, Robert C.
We present spectra of QSOs 1343+266 A B, covering Ly-beta to C~IV emission at 2\AA~resolution, and find further evidence that this system is not gravitationally lensed. We see, however, a large...