A5087689877- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- History and Developments in Astronomy
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Astro and Planetary Science
- Galaxies: Formation, Evolution, Phenomena
- Calibration and Measurement Techniques
- Infrared Target Detection Methodologies
- Astrophysical Phenomena and Observations
- Space Exploration and Technology
- CCD and CMOS Imaging Sensors
- Planetary Science and Exploration
- Research Data Management Practices
- Historical Astronomy and Related Studies
- Scientific Computing and Data Management
- Innovations in Educational Methods
- School Choice and Performance
- Optical Systems and Laser Technology
- Advanced optical system design
- Space exploration and regulation
- Medical Imaging Techniques and Applications
- International Science and Diplomacy
- Decision-Making and Behavioral Economics
Dominion Astrophysical Observatory
1987-2018
Herzberg Institute of Astrophysics
2000-2018
National Research Council Canada
1990-2018
New York University Press
2018
Cambridge University Press
2018
National Academies of Sciences, Engineering, and Medicine
2003-2014
Gemini South Observatory
2008-2010
Canada–France–Hawaii Telescope
2000-2005
University of Hawaii System
2005
Canadian Space Agency
2002
We report on time-series photometric observations in the earliest stages of superoutbursts extreme dwarf novae, AL Com and WZ Sge, which started 2001 May after 6 years quiescence July 23 quiescence, respectively. detected growth "early superhumps" during each rising stage. Our reject mass transfer instability for trigger superoutburst Sge stars, show existence some relations between spiral structure, gives a hint origin superhumps."
We have imaged five 7\arcmin \x 7\arcmin\ fields in M31 spanning galactocentric radii from 4 to 32 kpc along the SW-major axis. The were observed through two broad-band (\V\ and \I) narrow-band (\CN\ \TiO) filters. data used construct \IvsVI\ color-magnitude diagrams (CMDs) and, some of our fields, we found significant numbers stars Cepheid instability strip. A distance modulus for Cepheids middle field was that agreed well with other values literature values. width giant branch (GB) CMD all...
view Abstract Citations (63) References (25) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Complete Sample of Wide Binaries in the Solar Neighborhood Close, Laird M. ; Richer, Harvey B. Crabtree, Dennis R. well-defined sample unambiguously bound wide binaries solar neighborhood is presented. The appears complete for physical systems where s greater than 0.32 mpc, M(V) less 9.0, pi 0.040 arcsec or greater, and delta larger -12 deg. contains 39 systems,...
We present CCD photometry of red supergiant long-period variables (LPVs) in the Per OB1 association, Large Magellanic Cloud (LMC) and M33. The was obtained Kron-Cousins R I bandpasses a narrow bandpass (λ0=8250 Å, FWHM=300 Å) chosen to avoid TiO bands spectral energy distribution LPVs. Because strength varies greatly with temperature, which phase an LPV, avoiding reduces amplitude photometric variations seen result is lower dispersion well defined period-luminosity (PL) relation.
view Abstract Citations (64) References (44) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Late-Type Stellar of NGC 55 Pritchet, Christopher J. ; Richer, Harvey B. Schade, David Crabtree, Dennis Yee, H. K. C. authors have completed a photometric survey the late-type stellar content nearby galaxy 55. Using narrow-band filters they separated C and M stars, reached following conclusions: distance to is 1.34±0.08 Mpc. discrepancy between theoretical...
view Abstract Citations (48) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Detection of the Lensing Galaxy in PG 1115+080 Christian, C. A. ; Crabtree, D. Waddell, P. An image what is believed to be lensing galaxy quasar 1115 + 080 was obtained by using an RCA CCD at CFHT. The photometry R = 20.20 mag, V - about 0.70 mag and (B-V) least 0.75 mag. Comparison synthesized colors redshifted galaxies suggests that object may a spiral with z 0.3...
view Abstract Citations (64) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Luminous late-type stars in NGC 205. Richer, H. B. ; Crabtree, D. R. Pritchet, C. J. Broad band VRI and narrow CCD frames of the central region 205, which is dwarf elliptical companion Andromeda galaxy, are used to isolate TiO CN, as well separate M carbon unambiguously. Seven were found, together with 21 late-M whose spectral types cool about M5. If relative numbers...
The M33 galaxy is a nearby, relatively metal-poor, late-type spiral. Its proximity and almost face-on inclination means that it projects over large area on the sky, making an ideal candidate for wide-field CCD mosaic imaging. Photometry was obtained more than 10^6 stars covering 74' x 56' field centered M33. Main sequence (MS), supergiant branch (SGB), red giant (RGB) asymptotic (AGB) populations are identified classified based broad-band V I photometry. Narrow-band filters used to measure...
We present spectra of AGB stars in M31 for which observations had been previously secured using a four-band photometric system (FBPS). The FBPS used to identify M-, S-, and carbon-star (C-star) candidates, we use the show that did an excellent job at identifying C- M-stars. Of 48 C-stars were obtained, 7 have strongly enhanced ^13^C bands (J-stars), 2 strong Hα emission, while 3 are found exhibit Li absorption (Li-stars). Both J- Li-stars fainter than predicted by current theoretical models,...
view Abstract Citations (44) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Luminous late-type stars in NGC 300. Richer, H. B. ; Pritchet, C. J. Crabtree, D. R. A 15 square arcmin field 300 was observed through 4 filters with the CTIO m prime focus CCD. Two of were broad-band V and I other two isolated TiO (λ7800) CN (λ8100). With this filter set, it is possible to unambiguously distinguish carbon from M stars. Sixteen C 25 cool discovered...
view Abstract Citations (54) References (34) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Star and Cluster Formation in NGC 1275 Richer, Harvey B. ; Crabtree, Dennis R. Fabian, A. C. Lin, D. N. Imaging of the nuclear region central galaxy Perseus Cluster, 1275, has confirmed existence luminous, blue, unresolved objects Surrounding nucleus. A search archival material indicates that none these varied significantly over past 8 yr no new bright have either...
view Abstract Citations (72) References (13) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Broad-band near-infrared observations of Seyfert galaxies. McAlary, C. W. ; McLaren, R. A. Crabtree, D. The paper presents photometric 16 galaxies and three narrow-line emission Included in this sample are seven X-ray Seyferts. 2 observed dominated by a stellar continuum, as the Most 1 have power-law spectra near-infrared, but some show only continuum. All Seyferts...
view Abstract Citations (32) References (11) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Carbon stars in the Large Magellanic Cloud. Crabtree, D. R. ; Richer, H. B. Westerlund, E. The properties of seven carbon which are very likely members Cloud discussed. Three exhibit enhanced molecular bands C-13, while one bears a spectroscopic resemblance to peculiar Galactic star, WZ Cas. range bolometric absolute magnitude for is found be from -5.7 -6.6. By...
The primary scientific output from an astronomical telescope is the collection of papers published in refereed journals. A telescope's productivity measured by number which are based upon data taken with telescope. impact a paper can be quantitatively citations that receives. In this I will examine and over 20 telescopes, mainly optical/IR, apertures larger than 3.5-m for years between 2008 2012.
Abstract The Dominion Radio Astrophysical Observatory (DRAO) is carrying out a survey as part of an international collaboration to image the northe, at common resolution, in emission from all major constituents interstellar medium; neutral atomic gas, molecular ionised dust and relativistic plasma. For many these angular resolution images (1 arcmin) will be more than factor 10 better any previous studies. aim produce publicly-available database high high-dynamic range Galaxy for multi-phase...
Recent studies have shown that the proposal peer review processes employed by a variety of organizations to allocate astronomical telescope time produce outcomes are systematically biased depending on whether proposal's principal investigator (PI) is man or woman. Using Canada-France-Hawaii Telescope (CFHT) and Gemini Observatory statistics from Canada over 10 recent cycles, we assess not mean scores assigned National Research Council's (NRC's) Canadian Time Allocation Committee (CanTAC)...
We present the results of a deep photometric study outer halo NGC 1275, highly active cD galaxy at center Perseus cluster. find modest excess faint ($R > 22.5$) starlike objects in its halo, indicating population old-halo globular clusters. However, total estimated cluster corresponds to specific frequency $S_N = 4.4 \pm 1.2$, no larger than that normal giant ellipticals and three times lower other central galaxies such as M87. discuss several ideas for origin this galaxy. Our reinforce...
view Abstract Citations (24) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Late-Type Stars in an Inner and Far Disk Field of M31 Richer, Harvey B. ; Crabtree, Dennis R. Pritchet, Christopher J. Two disk fields M31, one Baade's field IV at 20 kpc from the nucleus galaxy other 4 kpc, were surveyed for late-type stars using broad-band V I filters (both fields) as well narrow-band outer field. The carbon to late M star ratio was found be 0.15,...
The primary scientific output from an astronomical telescope is the collection of papers published in refereed journals. A telescope's productivity measured by number which are based upon data taken with telescope. impact a paper can be quantitatively citations that receives. In this I will examine and CFHT, Gemini, Keck, Magellan, Subaru, UKIRT VLT telescopes using citation counts.
Gemini's Fast Turnaround program is intended to greatly decrease the time from having an idea acquiring supporting data. The scheme will offer monthly proposal submission opportunities, and proposals be reviewed by principal investigators or co-investigators of other submitted during same round. Here, we set out design system outline plan for its implementation, leading launch a pilot at Gemini North in January 2015.
We have examined the late-type stellar content of three disk fields in NGC 2403 using Cousins RI and VI CCD photometry. The AGB luminosity function has been constructed separately for inner outer fields. In both cases, relatively fewer bright stars are seen than LMC. shape innermost field is quite different from that LMC there an indication recent star formation may occurred. Several red blue supergiants H II regions also identified to support this. appears more similar LMC, a difference...
view Abstract Citations (28) References (15) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The circumstellar dust of MU Cephei. Rogers, C. ; Martin, P. G. Crabtree, D. R. An accurate solution to the equation transfer in spherical geometry (including an anisotropic phase function) is used model IUE observations extinction Mu Cep. Some grain materials can thus be eliminated from consideration while others restricted size (and envelope optical depth). Further...