... In order to obtain a quantitative estimate of the accuracy and reliability of our data reduction procedures and results, we have performed a data reduction pipeline based on the following steps: i) define a set of simulated HST-like images with synthetic globular cluster stellar distributions, which provide the ``true'' data for comparison; ii) convolve these images with appropriate assumptions of PSF and noise in order to construct simulated `` observed '' ... It contains 470 stars. b) ...

... The performance of each algorithm on the simulated lightcurves is scored accor ding to the rates of false positive (Type I) and false negative (Type II) errors. ... Combined: threshold normalization = 5 в 10 -4 References · Aschwanden, M.J., Nightingale, R.W. Tarball, T.D., & Wolfson, C.J. 2000, Ap J , 5 3 5 , 1 0 2 7 · Hudson, H.S. 1991, SoPh, 133, 357 Figure 3 Calibrating the event detection algorithms to optimize false positives, using the simulated lightcurves with zero events. ...

... In collaborative work with David Garc?a Alvarez (an Observatory PhD student now at Harvard) and John Butler, an extensive study of the RS CVn binary HR1099 was completed leading to two papers; the first on Doppler imaging and the second on flare activity. Spectra for the Doppler imaging were taken at two different sites, Kitt Peak National Observatory (KPNO), Arizona, and Mount Stromlo Observatory (MSO), Australia, during the 1998 MUltiSIte COntinuous Spectroscopic (MUSICOS) campaign. ...

... The Galactic low-mass X-ray binary GS 2023+338 was discovered during the burst on May 22, 1989 with the Japanise satellite Ginga (aka Galaxy). The flux reached 17 crabs (this unit of flux measurement is an bright X-ray source, Crab Nebula) at 10-35 keV. ... No other radio telescope worldwide carried out multi-frequency measurements. ... Upon 14 days the radio flux fell below the detection level at the RATAN-600 in relation to the decrease of the X-ray flux. ...

From the first published z > 3 survey of 21-cm absorption within the hosts of radio galaxies and quasars, we found an apparent dearth of cool neutral gas at high redshift. ... This indicates that he non-detection of 21-cm absorption is not due to the sensitivity limits of current radio telescopes, but rather that the lines-of-sight to the quasars, and probably the bulk of the host galaxies, are devoid of neutral gas. | ...

K-band Arcetri Obscured Supernova Search . What is the KAOSS Project? W hat is the KAOSS Project? Some recent surveys aimed at detecting Supernovae (SNe) in the optical have found that starburst galaxies do not show evidence for an enhanced SN rate, with respect to quiescent galaxies (Richmond et al. ... A similar result was obtained by Navasardyan et al. (2001) who looked for SNe in interacting galaxies, finding no evidence for correlations between SN rate and galaxy properties. ...

... In this activity, students will observe that the faintest stars which they can see in the sky are affected by many things: the adaptation of their eyes to the dark, the presence of clouds or haze, the time of year, and the presence of light pollution. General Information . ... After completing this activity, students should have a better understanding of the practical processes for dealing with the light pollution problem and with other environmental and societal issues. << previous page | ...

... Science . ... Science Users Information > Science Activities > APEX Science Verification > SHFI . ... Observing Facilities . ... Observing with ESO Telescopes . ... Telescope Time Allocation . ... ESO Data . ... The Science Verification (SV) observations of the APEX Swedish Heterodyne Facility Instrument were observed in March 2008. ... A selection of the APEX-1 proposals listed below have been observed during the week of joint SV observations in March 2008, and later during the ESO time of period...

... Precisely one month ago, on 11 July 2009, the last active area of the new solar cycle disappeared from the surface of the Sun. Over the 30 days following this, neither observers on Earth nor devices in space have been able to detect the emergence of any sunspots. ... Therefore, it seems that our star has once again returned to a state of deep solar "winter", following several sparks of activity in May-June 2009. ... To date, this period has lasted 30 days. ...

In this gallery are many images of Low Surface Brightness Galaxies which have recently been discovered and analyzed. ... The central surface brightness of this galaxy is 24.28 . Malin 2 This galaxy is another huge disk galaxy with a scale length of 15 kpc and a redshift of 15000 km/a. The high surface brightness knot in one of its spiral arms actu