Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userResearch Output from Lick Observatory for 1965-2019
46
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The productivity of Lick Observatory (LO) is reviewed over the years from 1965 to 2019, a 55 yr period which commences with the Shane 3 m telescope being the second-largest astronomical reflector in the world, but transitions into the era of 10 m ground-based optical telescopes. The metric of productivity used here is the annual number of refereed papers within which are presented results that are based at least in part on observations made with the telescopes of LO on Mount Hamilton. Criteria are set forth that have guided the counting of this metric. A bibliography of papers pertinent to observations from Lick Observatory has been compiled, and is made available through a NASA ADS library. The overall productivity of the observatory, counting all telescopes, went through a broad maximum between the years 1975 and 1982. This period also corresponds to a maximum in productivity of the Shane 3 m telescope. An author network shows that this period is attended by the introduction of digital detector systems at LO, particularly at the Shane telescope. Following 1983 the overall productivity of LO shows a net long-term decrease but with two other lesser peaks superimposed on that decrease. A slightly smaller peak occurs around 1996 and is associated with programs taking advantage of CCD spectrometers at both cassegrain and coud{e} foci of the Shane telescope. A third lesser peak around 2012 can be attributed to a rise in extragalactic supernova studies originating out of UC Berkeley. Author networks serve to document the UC astronomical communities that were using LO telescopes at these peak times. Institutional affiliations of first authors are documented.
rate research
Read More
The Automated Planet Finder (APF) is a facility purpose-built for the discovery and characterization of extrasolar planets through high-cadence Doppler velocimetry of the reflex barycentric accelerations of their host stars. Located atop Mt. Hamilton, the APF facility consists of a 2.4-m telescope and its Levy spectrometer, an optical echelle spectrometer optimized for precision Doppler velocimetry. APF features a fixed format spectral range from 374 nm - 970 nm, and delivers a Throughput (resolution * slit width product) of 114,000 arc-seconds, with spectral resolutions up to 150,000. Overall system efficiency (fraction of photons incident on the primary mirror that are detected by the science CCD) on blaze at 560 nm in planet-hunting mode is 15%. First-light tests on the RV standard stars HD 185144 and HD 9407 demonstrate sub-meter per second precision (RMS per observation) held over a 3-month period. This paper reviews the basic features of the telescope, dome, and spectrometer, and gives a brief summary of first-light performance.
A new high-order adaptive optics system is now being commissioned at the Lick Observatory Shane 3-meter telescope in California. This system uses a high return efficiency sodium beacon and a combination of low and high-order deformable mirrors to achieve diffraction-limited imaging over a wide spectrum of infrared science wavelengths covering 0.8 to 2.2 microns. We present the design performance goals and the first on-sky test results. We discuss several innovations that make this system a pathfinder for next generation AO systems. These include a unique woofer-tweeter control that provides full dynamic range correction from tip/tilt to 16 cycles, variable pupil sampling wavefront sensor, new enhanced silver coatings developed at UC Observatories that improve science and LGS throughput, and tight mechanical rigidity that enables a multi-hour diffraction- limited exposure in LGS mode for faint object spectroscopy science.
We searched through roughly 12 years of archival survey data acquired by the Katzman Automatic Imaging Telescope (KAIT) as part of the Lick Observatory Supernova Search (LOSS) in order to detect or place limits on possible progenitor outbursts of Type IIn supernovae (SNe~IIn). The KAIT database contains multiple pre-SN images for 5 SNe~IIn (plus one ambiguous case of a SN IIn/imposter) within 50 Mpc. No progenitor outbursts are found using the false discovery rate (FDR) statistical method in any of our targets. Instead, we derive limiting magnitudes (LMs) at the locations of the SNe. These limiting magnitudes (typically reaching $m_R approx 19.5,mathrm{mag}$) are compared to outbursts of SN 2009ip and $eta$ Car, plus additional simulated outbursts. We find that the data for SN 1999el and SN 2003dv are of sufficient quality to rule out events $sim40$ days before the main peak caused by initially faint SNe from blue supergiant (BSG) precursor stars, as in the cases of SN 2009ip and SN 2010mc. These SNe~IIn may thus have arisen from red supergiant progenitors, or they may have had a more rapid onset of circumstellar matter interaction. We also estimate the probability of detecting at least one outburst in our dataset to be $gtrsim60%$ for each type of the example outbursts, so the lack of any detections suggests that such outbursts are either typically less luminous (intrinsically or owing to dust) than $sim -13,mathrm{mag}$, or not very common among SNe~IIn within a few years prior to explosion.
This is the first paper of a series in which we present new measurements of the observed rates of supernovae (SNe) in the local Universe, determined from the Lick Observatory Supernova Search (LOSS). We have obtained 2.3 million observations of 14,882 sample galaxies over an interval of 11 years (March 1998 through Dec. 2008). We considered 1036 SNe detected in our sample and used an optimal subsample of 726 SNe (274 SNe~Ia, 116 SNe~Ibc, 324 SNe~II) to determine our SN rates. This is the largest and most homogeneous set of nearby SNe ever assembled for this purpose, and ours is the first local SN rate analysis based on CCD imaging and modern image-subtraction techniques. In this paper, we lay the foundation of the study. We derive the recipe for the control-time calculation for SNe with a known luminosity function, and provide details on the construction of the galaxy and SN samples used in the calculations. Compared with a complete volume-limited galaxy sample, our sample has a deficit of low-luminosity galaxies but still provides enough statistics for a reliable rate calculation. There is a strong Malmquist bias, so the average size (luminosity or mass) of the galaxies increases monotonically with distance, and this trend is used to showcase a correlation between SN rates and galaxy sizes. Very few core-collapse SNe are found in early-type galaxies, providing strong constraints on the amount of recent star formation within these galaxies. The small average observation interval ($sim 9$ days) of our survey ensures that our control-time calculations can tolerate a reasonable amount of uncertainty in the luminosity functions of SNe. We perform Monte Carlo simulations to determine the limiting magnitude of each image and the SN detection efficiency as a function of galaxy Hubble type ... (abridged)
The motivation, physics objectives, and technical strategy of a upgrade to the Pierre Auger Observatory are discussed.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
