Digitization and Scientific Exploitation of the Italian and Vatican Astronomical Plate Archives

Barbieri, C.; Blanco, C.; Bucciarelli, B.; Coluzzi, R.; Paola, Andrea; Lanteri, L.; Causi, Gian Luca Li; Marilli, E.; Massimino, P.; Mezzalira, Vincenzo; Mottola, S.; Nesci, R.; Omizzolo, A.; Pedichini, Fernando; Rampazzi, Francesca; Rossi, C.; Stagni, R.; Tsvetkov, Milcho; Viotti, R.

doi:10.1023/b:expa.0000028168.26442.30

Cited by 27 publications

(13 citation statements)

References 20 publications

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“…In addition, targetted new observations for another 16 epochs in the years 2006 to 2009 were taken with the CCD Schmidt camera of the Tautenburg 2 m telescope and with the focal reducer camera CAFOS at the 2.2 m telescope on Calar Alto 1 , Spain. Most of the archival photographic plates were digitized in the frame of the present work using the Tautenburg Plate Scanner (Brunzendorf & Meusinger, 1999) for the Tautenburg Schmidt plates, the highquality commercial scanner at the Asiago observatory (Barbieri et al 2003) for the Asiago plates, and the Microtek ScanMaker 9800XL for the Sonneberg astrograph plates. The Calar Alto plates were scanned for the Heidelberg Digitized Astronomical Plates (HDAP) project using a Heidelberger Druckmaschinen Nexscan F4100 professional scanner and are available from the German Astrophysical Virtual Observatory (GAVO) 2 .…”

Section: Optical Photometry: Long-term Light Curvementioning

confidence: 99%

J004457+4123 (Sharov 21): not a remarkable nova in M 31 but a background quasar with a spectacular UV flare

Meusinger¹,

Henze

Birkle

et al. 2010

A&A

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Aims. We announce the discovery of a quasar behind the disk of M 31, which was previously classified as a remarkable nova in our neighbour galaxy. It is shown here to be a quasar with a single strong flare where the UV flux has increased by a factor of ∼20. The present paper is primarily aimed at the remarkable outburst of J004457+4123 (Sharov 21), with the first part focussed on the optical spectroscopy and the improvement in the photometric database. Methods. We exploited the archives of photographic plates and CCD observations from 15 wide-field telescopes and performed targetted new observations. In the second part, we try to fit the flare by models of (1) gravitational microlensing due to a star in M 31 and (2) a tidal disruption event (TDE) of a star close to the supermassive black hole of the quasar. Results. Both the optical spectrum and the broad band spectral energy distribution of Sharov 21 are shown to be very similar to that of normal, radio-quiet type 1 quasars. We present photometric data covering more than a century and resulting in a long-term light curve that is densely sampled over the past five decades. The variability of the quasar is characterized by a ground state with typical fluctuation amplitudes of ∼0.2 mag aroundB ∼ 20.5, superimposed by a singular flare of ∼2 yr duration (observer frame) with the maximum at 1992.81. The total energy in the flare is at least three orders of magnitudes higher than the radiated energy of the most luminous supernovae, provided that it comes from an intrinsic process and the energy is radiated isotropically. The profile of the flare light curve is asymmetric showing in particular a sudden increase before the maximum, whereas the decreasing part can be roughly approximated by a t −5/3 power law. Both properties appear to support the standard TDE scenario where a ∼10 M giant star was shredded in the tidal field of a ∼2 . . . 5 × 10 8 M black hole. The short fallback time derived from the observed light curve requires an ultra-close encounter where the pericentre of the stellar orbit is deep within the tidal disruption radius. This simple model neglects, however, the influence of the massive accretion disk, as well as general-relativistic effects on the orbit of the tidal debris. Gravitational microlensing probably provides an alternative explanation, although the probability of such a high amplification event is very low.

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Section: Optical Photometry: Long-term Light Curvementioning

confidence: 99%

J004457+4123 (Sharov 21): not a remarkable nova in M 31 but a background quasar with a spectacular UV flare

Meusinger¹,

Henze

Birkle

et al. 2010

A&A

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“…The sample of 87 plates that is considered in this paper is drawn from the following sources: 9 1. There are 26 plates from Asiago Observatory, the same archive from which the sample in Paper I was drawn (Barbieri et al 2003). However, whereas the previously analyzed plates were taken with the 67/92 cm Schmidt telescope, the plates in the present sample were taken with the 40/50 cm Schmidt telescope and the 1.22 m Galilei telescope.…”

Section: The Platesmentioning

confidence: 99%

The History of the Mysterious Eclipses of KH 15D. II. Asiago, Kiso, Kitt Peak, Mount Wilson, Palomar, Tautenburg, and Rozhen Observatories, 1954-1997

et al. 2005

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The unusual pre-main-sequence binary star KH 15D undergoes remarkably deep and long-lasting periodic eclipses. Some clues about the reason for these eclipses have come from the observed evolution of the system's light curve over the last century. Here we present UBVRI photometry of KH 15D from 1954 to 1997 based on photographic plates from various observatories. The system has been variable at the %1 mag level since at least 1965. There is no evidence of color variations, with a typical limit of Á(B À V ) < 0:2 mag. We confirm some previously published results that were based on a smaller sample of plates: from approximately 1965 to 1990, the total flux was modulated with the 48 day orbital period of the binary, but the maximum flux was larger, the fractional variations were smaller, and the phase of minimum flux was shifted by almost a half-cycle relative to the modern light curve. All these results are consistent with the recently proposed theory that KH 15D is being occulted by an inclined, precessing, circumbinary ring.

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“…Shared storage across multiple servers (Sacks, 2001). Widely used in astronomical data archiving (Barbieri et al, 2003;Balard et al, 2006). 1) Inefficient storage speed and hardly meet the requirement of NVST high performance storage.…”

Section: Control Computersmentioning

confidence: 99%

Low-cost high performance distributed data storage for multi-channel observations

et al. 2015

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The New Vacuum Solar Telescope (NVST) is a 1-meter solar telescope that aims to observe the fine structures in both the photosphere and the chromosphere of the Sun. The observational data acquired simultaneously from one channel for the chromosphere and two channels for the photosphere bring great challenges to the data storage of NVST. The multi-channel instruments of NVST, including scientific cameras and multi-band spectrometers, generate at least 3 terabytes data per day and require high access performance while storing massive short-exposure images. It is worth studying and implementing a storage system for NVST which would balance the data availability, access performance and the cost of development. In this paper, we build a distributed data storage system (DDSS) for NVST and then deeply evaluate the availability of real-time data storage on a distributed computing environment. The experimental results show that two factors, i.e., the number of concurrent read/write and the file size, are critically important for improving the performance of data access on a distributed environment. Referring to these two factors, three strategies for storing FITS files are presented and implemented to ensure the access performance of the DDSS under conditions of multi-host write and read simultaneously. The real applications of the DDSS proves that the system is capable of meeting the requirements of NVST real-time high performance observational data storage. Our study on the DDSS is the first attempt for modern astronomical telescope systems to store real-time observational data on a low-cost distributed system. The research results and corresponding techniques of the DDSS provide a new option for designing real-time massive astronomical data storage system and will be a reference for future astronomical data storage.

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Digitization and Scientific Exploitation of the Italian and Vatican Astronomical Plate Archives

Cited by 27 publications

References 20 publications

J004457+4123 (Sharov 21): not a remarkable nova in M 31 but a background quasar with a spectacular UV flare

J004457+4123 (Sharov 21): not a remarkable nova in M 31 but a background quasar with a spectacular UV flare

The History of the Mysterious Eclipses of KH 15D. II. Asiago, Kiso, Kitt Peak, Mount Wilson, Palomar, Tautenburg, and Rozhen Observatories, 1954-1997

Low-cost high performance distributed data storage for multi-channel observations

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