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Search Results: 1 - 10 of 219580 matches for " C. Corbally "
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Young stars in the Camelopardalis dust and molecular clouds. V. More YSOs confirmed spectroscopically
C. J. Corbally,V. Straizys
Physics , 2009,
Abstract: Far red spectra for 22 stars in the Camelopardalis and the northern Perseus dark clouds, suspected to be pre-main-sequence objects (YSOs), are obtained. This evolutionary status is confirmed for ten stars located in the dust and molecular cloud close to the high-mass protostar GL 490, four stars near the H II region Sh2-205 and one star in the dark cloud TGU 1041. All of these objects exhibit emission in the H alpha line and some of them emission in the O I and Ca II lines. The spectral energy distributions, equivalent widths of the emission lines and approximate spectral classes are determined. Evolutionary stages of the stars are estimated from 2MASS, IRAS and MSX infrared photometry. Now we have spectral confirmation of the YSO status for 14 stars in the GL 490 area and 8 stars at Sh2-205. Their spectral types are from A to K, but most of them are either Herbig Ae stars or intermediate objects between T Tauri type and Herbig stars. Both these star forming regions are located near the outer edge of the Local arm at a distance of 900 pc.
Spectral analysis of YSOs and other emission-line stars in the North America and Pelican nebulae region
C. J. Corbally,V. Straizys,V. Laugalys
Physics , 2009,
Abstract: Far red spectra for 34 stars with V magnitudes between 15 and 18 in the direction of the North America and Pelican nebulae (NAP) star-forming region are obtained. Some of these stars were known earlier as emission-line objects, others were suspected as pre-main-sequence stars from photometry in the J, H, Ks and Vilnius systems. We confirm the presence of the H alpha line emission in the spectra of 19 stars, some of them exhibit also emission in the O I and Ca II lines. In some of the stars the H alpha absorption line is filled with emission. To estimate their evolutionary status, the spectral energy distributions, based on Vilnius, 2MASS, MSX and Spitzer photometry, are applied. Only eight emission-line stars are found to be located at a distance of the NAP complex. Others are either chromospherically active stars in front of the complex or distant luminous stars with H alpha absorption and emission components. For five stars with faint emission the data are not sufficient to estimate their distance. One star is found to be a heavily reddened K-supergiant located in the Outer arm. The stars, for which we failed to confirm the emission in H alpha, are mostly red dwarfs located in front of the NAP complex, two of them could be binaries with L-type components. Taking into account the stars suspected to be YSOs by their 2MASS colors we conclude that the NAP complex can possess a considerable population of young stars hidden behind the dust cloud.
Mining the local Universe: the QSO space density
S. Cristiani,A. Grazian,A. Omizzolo,C. Corbally
Physics , 2000, DOI: 10.1007/10849171_11
Abstract: We present progress results of a new survey for bright QSOs (V<14.5, R<15.4, B_J<15.2) covering the whole sky at high galactic latitudes, |b|>30. The surface density of QSOs brighter than B_J=14.8 turns out to be 2.9 +- 0.8 10^{-3} deg^{-2}. The optical Luminosity Function at 0.04 < z < 0.3 shows significant departures from the standard pure luminosity evolution, providing new insights in the modelling of the QSO phenomenon.
Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I
R. O. Gray,C. J. Corbally,R. F. Garrison,M. T. McFadden,P. E. Robinson
Physics , 2003, DOI: 10.1086/378365
Abstract: We have embarked on a project, under the aegis of the Nearby Stars (NStars)/ Space Interferometry Mission Preparatory Science Program to obtain spectra, spectral types, and, where feasible, basic physical parameters for the 3600 dwarf and giant stars earlier than M0 within 40 parsecs of the sun. In this paper we report on the results of this project for the first 664 stars in the northern hemisphere. These results include precise, homogeneous spectral types, basic physical parameters (including the effective temperature, surface gravity and the overall metallicity, [M/H]) and measures of the chromospheric activity of our program stars. Observed and derived data presented in this paper are also available on the project's website at http://stellar.phys.appstate.edu/ .
The Asiago-ESO/RASS QSO Survey II. The Southern Sample
A. Grazian,A. Omizzolo,C. Corbally,S. Cristiani,M. G. Haehnelt,E. Vanzella
Physics , 2002, DOI: 10.1086/343834
Abstract: This is the second paper of a series describing the Asiago-ESO/RASS QSO survey, a project aimed at the construction of an all-sky statistically well-defined sample of very bright QSOs (B_J < 15). Such a survey is required to remove the present uncertainties about the properties of the local QSO population and constitutes an homogeneous database for detailed evolutionary studies of AGN. We present here the complete Southern Sample, which comprises 243 bright (12.60 < B_J < 15.13) QSO candidates at high galactic latitudes (|b_{gal}| > 30^{\circ}). The area covered by the survey is 5660 sq. deg. Spectroscopy for the 137 still unidentified objects has been obtained. The total number of AGN turns out to be 111, 63 of which are new identifications. The properties of the selection are discussed. The completeness and the success rate for this survey at the final stage are 63% and 46%, respectively.
Can we Improve Patient Safety?
Martin T. Corbally
Frontiers in Pediatrics , 2014, DOI: 10.3389/fped.2014.00098
Abstract: Despite greater awareness of patient safety issues especially in the operating room and the widespread implementation of surgical time out (WHO),errors, especially wrong site surgery, continue. Most such errors are due to lapses in communication where decision makers fail to consult or confirm operative findings but worryingly where parental concerns over the planned procedure are ignored or not followed through. The WHO surgical pause / Time Out aims to capture these errors and prevent them but the combination of human error and complex hospital environments can overwhelm even robust safety structures and simple common sense. Parents are the ultimate repository of information on their child's condition and planned surgery but are traditionally excluded from the process of Surgical pause and Time Out perhaps to avoid additional stress. In addition surgeons, like pilots, are subject to the phenomenon of "plan continue fail" with potentially disastrous outcomes.
The Young Solar Analogs Project: I. Spectroscopic and Photometric Methods and Multi-year Timescale Spectroscopic Results
R. O. Gray,J. M. Saken,C. J. Corbally,M. M. Briley,R. A. Lambert,V. A. Fuller,I. M. Newsome,M. F. Seeds,Y. Kahvaz
Physics , 2015,
Abstract: This is the first in a series of papers presenting methods and results from the Young Solar Analogs Project, which began in 2007. This project monitors both spectroscopically and photometrically a set of 31 young (300 - 1500 Myr) solar-type stars with the goal of gaining insight into the space environment of the Earth during the period when life first appeared. From our spectroscopic observations we derive the Mount Wilson $S$ chromospheric activity index ($S_{\rm MW}$), and describe the method we use to transform our instrumental indices to $S_{\rm MW}$ without the need for a color term. We introduce three photospheric indices based on strong absorption features in the blue-violet spectrum -- the G-band, the Ca I resonance line, and the Hydrogen-$\gamma$ line -- with the expectation that these indices might prove to be useful in detecting variations in the surface temperatures of active solar-type stars. We also describe our photometric program, and in particular our "Superstar technique" for differential photometry which, instead of relying on a handful of comparison stars, uses the photon flux in the entire star field in the CCD image to derive the program star magnitude. We present time series plots of our spectroscopic data for all four indices, and carry out extensive statistical tests on those time series demonstrating the reality of variations on timescales of years in all four indices. We also statistically test for and discover correlations and anti-correlations between the four indices. We discuss the physical basis of those correlations. As it turns out, the "photospheric" indices appear to be most strongly affected by continuum emission. We thus anticipate that these indices may prove to be useful proxies for monitoring continuum emission in the near ultraviolet.
An Encoding System to Represent Stellar Spectral Classes in Archival Databases and Catalogs
Myron A. Smith,Randall W. Thompson,Richard O. Gray,Christopher Corbally,Inga Kamp
Physics , 2011,
Abstract: The data archives from space and ground-based telescopes present a vast opportunity for the astronomical community. We describe a classification encoding system for stellar spectra designed for archival databases that organizes the spectral data by "spectral classes." These classes are encoded into a digital format of the form TT.tt.LL.PPPP, where TT and tt refer to spectral type and subtype, LL to luminosity class, and PPPP to possible spectral peculiarities. Archive centers may wish to utilize this system to quantify classes of formerly arbitrary spectral classification strings found in classification catalogs corresponding to datasets of pointed spectroscopic observations in their holdings. The encoding system will also allow users to request archived data based on spectral class ranges, thereby streamlining an otherwise tedious data discovery process. Material in Appendix A is "normative" (part of the defined standard). Appendices B and C are "informative," meant to show how one data provider (MAST) has opted to handle some practical details.
The Distance to SN 1999em from the Expanding Photosphere Method
M. Hamuy,P. A. Pinto,J. Maza,N. B. Suntzeff,M. M. Phillips,R. G. Eastman,R. C. Smith,C. J. Corbally,D. Burstein,Y. Li,V. Ivanov,A. Moro-Martin,L. G. Strolger,R. E. de Souza,S. dos Anjos,E. M. Green,T. E. Pickering,L. Gonzalez,R. Antezana,M. Wischnjewsky,G. Galaz,M. Roth,S. E. Persson,W. L. Freedman,R. A. Schommer
Physics , 2001, DOI: 10.1086/322450
Abstract: We present optical and IR spectroscopy of the first two months of evolution of the Type II SN 1999em. We combine these data with high-quality optical/IR photometry beginning only three days after shock breakout, in order to study the performance of the ``Expanding Photosphere Method'' (EPM) in the determination of distances. With this purpose we develop a technique to measure accurate photospheric velocities by cross-correlating observed and model spectra. The application of this technique to SN 1999em shows that we can reach an average uncertainty of 11% in velocity from an individual spectrum. Our analysis shows that EPM is quite robust to the effects of dust. In particular, the distances derived from the VI filters change by only 7% when the adopted visual extinction in the host galaxy is varied by 0.45 mag. The superb time sampling of the BVIZJHK light-curves of SN 1999em permits us to study the internal consistency of EPM and test the dilution factors computed from atmosphere models for Type II plateau supernovae. We find that, in the first week since explosion, the EPM distances are up to 50% lower than the average, possibly due the presence of circumstellar material. Over the following 65 days, on the other hand, our tests lend strong credence to the atmosphere models, and confirm previous claims that EPM can produce consistent distances without having to craft specific models to each supernova. This is particularly true for the VI filters which yield distances with an internal consistency of 4%. From the whole set of BVIZJHK photometry, we obtain an average distance of 7.5+/-0.5 Mpc, where the quoted uncertainty (7%) is a conservative estimate of the internal precision of the method obtained from the analysis of the first 70 days of the supernova evolution.
LAMOST observations in the Kepler field. Database of low-resolution spectra
P. De Cat,J. N. Fu,A. B. Ren,X. H. Yang,J. R. Shi,A. L. Luo,M. Yang,J. L. Wang,H. T. Zhang,H. M. Shi,W. Zhang,Subo Dong,G. Catanzaro,C. J. Corbally,A. Frasca,R. O. Gray,J. Molenda-Zakowicz,K. Uytterhoeven,M. Briquet,H. Bruntt,S. Frandsen,L. Kiss,D. W. Kurtz,M. Marconi,E. Niemczura,R. H. Oestensen,V. Ripepi,B. Smalley,J. Southworth,R. Szabo,J. H. Telting,C. Karoff,V. Silva Aguirre,Y. Wu,Y. H. Hou,G. Jin,X. L. Zhou
Physics , 2015, DOI: 10.1088/0067-0049/220/1/19
Abstract: The nearly continuous light curves with micromagnitude precision provided by the space mission Kepler are revolutionising our view of pulsating stars. They have revealed a vast sea of low-amplitude pulsation modes that were undetectable from Earth. The long time base of Kepler light curves allows an accurate determination of frequencies and amplitudes of pulsation modes needed for in-depth asteroseismic modeling. However, for an asteroseismic study to be successful, the first estimates of stellar parameters need to be known and they can not be derived from the Kepler photometry itself. The Kepler Input Catalog (KIC) provides values for the effective temperature, the surface gravity and the metallicity, but not always with a sufficient accuracy. Moreover, information on the chemical composition and rotation rate is lacking. We are collecting low-resolution spectra for objects in the Kepler field of view with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST, Xinglong observatory, China). All of the requested fields have now been observed at least once. In this paper we describe those observations and provide a database of use to the whole astronomical community.
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