Download or read book The Galactic Center Stellar Population in the Near Infrared written by Joseph William Haller and published by . This book was released on 1992 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of the Stellar Population and Dynamical Environment of the Milky Way Galactic Center with Near infrared Adaptive Optics Photometry written by Abhimat Krishna Gautam and published by . This book was released on 2020 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proximity of the Milky Way Galactic center (GC) allows a unique perspective into how supermassive black holes (SMBHs) affect their surrounding stellar population. Several uncertainties still remain about the stellar population at the GC, notably the frequency of binary star systems at the GC and the distribution of dark stellar remnants surrounding the SMBH. In this thesis, we used over 13 years of Keck Observatory adaptive optics (AO) photometric flux measurements of the stellar population within approximately a half parsec of the GC SMBH in an effort to address the uncertainties about the GC stellar binary population and to probe the density of unseen stars or compact objects near the SMBH. First, we present an 11.5 year adaptive optics (AO) study of stellar variability and search for eclipsing binaries in the central 0.4 pc ( 10 ) of the Milky Way nuclear star cluster. In the study, we measured the photometry of 563 stars using the Keck II NIRC2 imager (K -band, 0 = 2.124 m). We achieved a photometric uncertainty floor of mK 0.03 ( 3%), comparable to the highest precision achieved in other AO studies. Approximately half of our sample (50 2%) shows variability. 52 5% of known early-type young stars and 43 4% of known late-type giants are variable. These variability fractions are higher than those of other young, massive star populations or late-type giants in globular clusters, and can be largely explained by two factors. First, our experiment time baseline is sensitive to long-term intrinsic stellar variability. Second, the proper motion of stars behind spatial inhomogeneities in the foreground extinction screen can lead to variability. We recovered the two known Galactic center eclipsing binary systems: IRS 16SW and S4-258 (E60). We constrained the Galactic center eclipsing binary fraction of known early-type stars to be at least 2.4 1.7%. We found no evidence of an eclipsing binary among the young S-stars nor among the young stellar disk members. These results are consistent with the local OB eclipsing binary fraction. We additionally identified a new periodic variable at the GC, S2-36, with a 39.43 day photometric period. Second, we present the discovery of the first known eclipsing, ellipsoidal binary star system (S2-36) at the GC, with a binary orbital period of 78.8 days at a projected distance of 2 arcsec from Sgr A*. As the first dynamically soft stellar binary discovered in the region, S2-36 offers powerful constraints on the dark cusp density within 0.1 pc of the SMBH. We used new and existing near-infrared adaptive optics Keck Observatory imaging data collected over 13 years to measure the photometric and astrometric properties of S2-36. S2-36's proper motion suggests a distance
Download or read book Early type Galaxy Stellar Populations in the Near infrared written by Christina Baldwin and published by . This book was released on 2014 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stellar population synthesis (SPS) models are key to interpreting the spectral energy distributions of galaxies. While different models typically agree at optic wavelengths, these same models give vastly different predictions in the near-infrared, mainly due to different treatments of late-stage stellar evolution, in particular the Thermally Pulsing Asymptitic Giant Branch (TP-AGB) phase. This thesis tests three popular SPS models, with a focus on evaluating the different treatments of this phase.
Download or read book Spiral Galaxies in the Near IR written by Dante Minniti and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: From June 7-9, 1995, the European Southern Observatory (ESO) and the Max Plank Institut fiir Astrophysik (MPA) jointly held the Workshop on Spiral Galaxies in the Near-IR. This meeting took place at the ESO headquarters in Garching bei Miinchen, Germany. The weather waschanging, with the biergarten closed, but that did not stop 85 people from allover the world from attending the meeting. The three days were intensive, with talks and coffee and posters from 9 am to 6 pm, and very productive indeed for everyone. The topics covered the stellar populations of the Milky Way and other more distant spirals, the role of dust, the dynamics of spiral galaxies, and the nuclear activity seen at near-IR wavelengths. This volume presents the original contributions from the participants, including several papers that review the state-of-the-art knowledge in these various subjects. The editors would like to thank first and foremost Christina Stoffer, for she took care of everything. The meeting would not have been so successful without her expertise and efficiency. We are deeply indebted to the directors of MPA and ESO Science, Simon White and Jacqueline Bergeron, for their support and encouragement. We would also like to thank the other members of the scientific organizing committee: R. Genzel, K. Freeman, A. Moorwood, S. White, M. Rieke and E. Athannasoula, for their advice with the organization of the program. We also thank G. Rieke, R. Genzel, L. Athannasoula, A. Renzini and R.
Download or read book Science with Astronomical Near Infrared Sky Surveys written by N. Epchtein and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: Outstanding progress in near-infrared detection technology and in real-time image processing has led astronomers to start undertaking all-sky surveys in the 1--2 mum range (project DENIS in Europe and 2MASS in the U.S.A.), surveys which will have a considerable impact in various areas of astronomy. This book gathers the contributions of more than 80 specialists involved in fields of interest as different as low mass stars, late stages of stellar evolution, star formation, stellar populations of the Galaxy and the Magellanic Clouds, the local structure of the Universe, and observational cosmology. It describes the impact on these fields of the exhaustive data bases and catalogs of stars and galaxies that these surveys will provide. The considerable interest of these documents for the future of infrared space and ground-based projects and the complementarity with other currently ongoing or planned surveys in other spectral ranges are emphasized.
Download or read book Near infrared Polarimetry and Stellar Classification in the Galactic Center written by Rainer Buchholz and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Infrared Astronomy with Arrays written by Ian S. McLean and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 607 pages. Available in PDF, EPUB and Kindle. Book excerpt: The idea for another conference on the theme of Infrared Astronomy with Arrays actually goes back to March 1987. At a party held in my home at the end of the Hilo conference, excitement was running high and everyone present was in favor of another meeting. I recall suggesting to Al Fowler that the next meeting could be in Tucson. Despite Al's reply to the effect that Hawaii was a much nicer location, a meeting was held in Tucson three years later. That meeting focussed more on the astrophysics which had been accomplished with the detectors, rather than on techniques and methods. However, it was already apparent in February of 1990 that a new generation of larger m arrays would soon supersede the 64x64 class of devices and so, having just moved from the UK Infrared Telescope unit in Hawaii to join with Eric Becklin in his move to UCLA, it seemed to me that another Hilo-style conference was appropriate, and Eric agreed.
Download or read book Ten Thousand Stars and One Black Hole written by Sascha Trippe and published by . This book was released on 2008 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Center of the Galaxy written by Mark Morris and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation of the Galactic nucleus and its surroundings is necessarily a modem endeavor, for traditional observations made at visual wavelengths have not even begun to penetrate the veil of -30 magnitudes of visual extinction that intercedes. On the other hand, infrared, and especially radio observers find a relatively unobstructed view of the central portion of the Galaxy, so the study of this arena has proceeded apace with the development of these branches of astronomy. Thus, it is no accident that the first IAU sponsored conference to be held on the Galactic center is timed to coincide with the initiation, or the immediate aftennath, of major technical developments at long wavelengths, including infrared array detectors, millimeter-wavelength aperture synthesis, and self-calibration and refmed deconvolution algorithms in aperture synthesis radio astronomy. The center of the Galaxy is also accessible to X and gamma-ray observers, and progress at high energies has been steady, especially as imaging capabilities are being realized at X-ray wavelengths. However, one might expect that the revolution in the high energy domain is still ahead of us, as instruments with larger collecting areas and improved spatial resolution are now being developed. The youth of this subject is evidenced by the relatively small number of meetings that have been devoted to it.
Download or read book Behind Closed Curtains written by Nicole L. Homeier and published by . This book was released on 2003 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Galactic and Extragalactic Background Radiation written by International Astronomical Union. Symposium and published by Springer Science & Business Media. This book was released on 1990-08-31 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the 139th Symposium of the International Astronomical Union on `The Galactic and Extragalactic Background Radiation, held in Heidelberg, FRG, June 12-16, 1989
Download or read book The Stellar Populations of Galaxies written by B. Barbuy and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: One approach to learning about stellar populations is to study them at three different levels of resolution. First in our own Galaxy; secondly from nearby galaxies where stars can still be resolved; and thirdly in remote galaxies in which the stellar population can only be studied in integrated light. This IAU Symposium covered the entire range of galaxies in its study of their stellar populations. Interspersed with theoretical papers, the wealth of observational results provides an important state-of-the-art presentation of the progress that has been made in this field.
Download or read book Proceedings of the Galactic Center Workshop 2002 Astronomische Nachrichten Supplementary Issue 1 2003 written by Angela Cotera and published by John Wiley & Sons. This book was released on 2008-09-26 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our knowledge of the environment of the nucleus of our galaxy has been greatly enhanced, by more extensive and sensitive observations at radio and infrared wavelengths, the advent of high resolution x-ray imaging and spectroscopy, and considerable theoretical activity to understand the nucleus and its components, and their activity. The Galactic Center Workshop 2002 was organized to review recent research on the galactic center, including the latest state-of-the-art observations and important theoretical developments. The workshop covered phenomena on scales ranging from the central several hundred parsecs to the central parsec and within. Each topic was approached from both multi-wavelength observational and theoretical perspectives.
Download or read book Infrared Spectroscopy in Astronomy written by Brigitte Kaldeich-Schürmann and published by . This book was released on 1989 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Nuclei of Normal Galaxies written by R. Genzel and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our Galactic center's proximity allows astronomers to study physical pro cesses within galactic nuclei at a level of detail that will never be possible in the more distant, but usually also more spectacular, extragalactic systems. Recent advances in instrumentation from the radio, through the submillime ter and infrared wavebands, and out to the X- and "'(-ray bands now allow observations of the Galactic Center over thirteen orders of magnitude in wave length. Our knowledge about the central few hundred parsecs of our Galaxy has consequently increased vastly over the past decade. The same new instru ments provide high resolution, high quality measurements of nearby ''normal'' galactic nuclei; that is, nuclei whose modest energy output is comparable to that of our own (and most other) galaxies. Theorists, spurred in part by the new observations, have been able to refine models of the energetics, dynam ics, and evolution of the gas and stellar systems deep within galactic nuclei.
Download or read book Astrophysics with Infrared Arrays written by Richard Elston and published by . This book was released on 1990 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Galactic and Extragalactic Star Formation written by Ralph E. Pudritz and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent advances in the instrumentation used to observe star forming regions in both our own Milky Way and in external galaxies have transformed the subject from a phenomenological pursuit into an increasingly unified, physical science. High resolution centimetre, millimetre, infrared, and optical studies of local star forming clouds have allowed us to probe the physics of star formation down to spatial scales approaching those of the solar system. These developments make it possible to better constrain the basic physical processes underlying star formation itself. At the same time, these new instruments have placed extragalactic studies on a footing detailed enough to allow comparison with star forming regions within our own galaxy. This revolution means that we will soon be able to link the physics of local star forming regions to the global star forming properties of galaxies. The entire structure of this NATO Advanced Study Institute was designed to explore this new view of the subject. This Institute on "Galactic and Extragalactic Star Formation" was held from June 21 -July 4, 1987 at the Conference Centre in the village of Whistler, British Columbia, Canada. The informal atmosphere of this lovely mountain resort stim ulated many valuable scientific exchanges. The Institute was funded by a major grant from NATO Scientific Affairs. Additional financial and I.I1oral assistance was provided by the Canadian Institute for Theoretical Astrophysics (CITA) and Mc Master University.
