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We present results of Doppler tomography of the pre-outburst accretion disk in SS Cygni. Analysis of Doppler tomograms shows that the the following gas dynamic details exist in the disk: ``hot line''; spiral tidal shock; and a bow... more
We present results of Doppler tomography of the pre-outburst accretion disk in SS Cygni. Analysis of Doppler tomograms shows that the the following gas dynamic details exist in the disk: ``hot line''; spiral tidal shock; and a bow shock. Comparison of tomograms constructed using results obtained in different epochs shows that by the outburst the density of the disk increases and its radius becomes larger.
A new fast photometer based on SiPM technology was developed at the University of Rome "La Sapienza" starting from 2009. A first prototype was successfully tested observing the Crab pulsar at the Loiano telescope of the Bologna... more
A new fast photometer based on SiPM technology was developed at the University of Rome "La Sapienza" starting from 2009. A first prototype was successfully tested observing the Crab pulsar at the Loiano telescope of the Bologna Observatory. In this paper we illustrate the improvements we applied to our instrument, concerning new cooled commercial sensors, a new version of our custom dedicated electronics and an upgraded control timing software. Finally we report the results obtained with this instrument on December 2012 on the Crab pulsar at the Loiano telescope to show its goodness and capabilities.
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ABSTRACT We observed one full transit of HAT-P-5 on the night of 2010 August 23, using the 2.2-m telescope and BUSCA imager at Calar Alto Astronomical Observatory. BUSCA uses dichroics to split the incoming light into four wavelength... more
ABSTRACT We observed one full transit of HAT-P-5 on the night of 2010 August 23, using the 2.2-m telescope and BUSCA imager at Calar Alto Astronomical Observatory. BUSCA uses dichroics to split the incoming light into four wavelength intervals, which traverse different arms of the instrument and are incident on to four CCDs. We observed two transits of HAT-P-5 in 2011 May and July, using BFOSC mounted on the 1.52-m G.D. Cassini Telescope at Loiano Observatory, Italy. (2 data files).
For both planetary systems, we observed one transit event simultaneously with two telescopes (Figs. 1 and 2). These observations were carried out between September and October 2012 with the 1.52m Cassini telescope from the Loiano... more
For both planetary systems, we observed one transit event simultaneously with two telescopes (Figs. 1 and 2). These observations were carried out between September and October 2012 with the 1.52m Cassini telescope from the Loiano observatory and with the 1.23m Calar Alto telescope. An additional transit of HAT-P-16 was observed on October 29th 2010 from Loiano during the PLAN microlensing campaign towards M31 (Calchi Novati et al. 2009ApJ...695..442N, 2010ApJ...717..987C). Another transit of HAT-P-16 was observed in Calar Alto on August 22th 2011. In total we present six new light curves, five of them being from defocussed 1.2-1.5m telescopes (see table 1). File contain the data used to plot the lightcurves in Fig. 3 and 4 in the paper. (7 data files).
In order to identify the nature of the active nucleus of spiral galaxy NGC 4992, associated with the Chandra and INTEGRAL high-energy sources CXOU J130905.6+113803 and IGR J13091+1137 (see Halpern, Atel #572 and Sazonov et al., 2005, A&A,... more
In order to identify the nature of the active nucleus of spiral galaxy NGC 4992, associated with the Chandra and INTEGRAL high-energy sources CXOU J130905.6+113803 and IGR J13091+1137 (see Halpern, Atel #572 and Sazonov et al., 2005, A&A, 444, L37), we acquired a 15-minute optical spectrum on February 1, 2006 with the instrument BFOSC mounted on the `G.D. Cassini' 1.5m
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ABSTRACT We present high-precision photometry of three transits of the extrasolar planetary system WASP-2, obtained by defocussing the telescope, and achieving point-to-point scatters of between 0.42 and 0.73 mmag. These data are modelled... more
ABSTRACT We present high-precision photometry of three transits of the extrasolar planetary system WASP-2, obtained by defocussing the telescope, and achieving point-to-point scatters of between 0.42 and 0.73 mmag. These data are modelled using the JKTEBOP code, and taking into account the light from the recently-discovered faint star close to the system. The physical properties of the WASP-2 system are derived using tabulated predictions from five different sets of stellar evolutionary models, allowing both statistical and systematic errorbars to be specified. We find the mass and radius of the planet to be M_b = 0.847 +/- 0.038 +/- 0.024 Mjup and R_b = 1.044 +/- 0.029 +/- 0.015 Rjup. It has a low equilibrium temperature of 1280 +/- 21 K, in agreement with a recent finding that it does not have an atmospheric temperature inversion. The first of our transit datasets has a scatter of only 0.42 mmag with respect to the best-fitting light curve model, which to our knowledge is a record for ground-based observations of a transiting extrasolar planet. Comment: Accepted for publication in MNRAS. 9 pages, 3 figures, 10 tables
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Title: GRB 060124 optical observations. Authors: Bhatt, BC; Sahu, DK; Srividya, S.; Chakradhari, NK. Publication: GRB Coordinates Network, Circular Service, 4597, 1 (2006). Publication Date: 00/2006. Origin: SIMBAD. Bibliographic Code:... more
Title: GRB 060124 optical observations. Authors: Bhatt, BC; Sahu, DK; Srividya, S.; Chakradhari, NK. Publication: GRB Coordinates Network, Circular Service, 4597, 1 (2006). Publication Date: 00/2006. Origin: SIMBAD. Bibliographic Code: 2006GCN..4597....1B. Abstract. ...