Elisa Distefano - Academia.edu (original) (raw)

Papers by Elisa Distefano

The table reported is the complete log of observations of the campaign made with the REM telescop... more The table reported is the complete log of observations of the campaign made with the REM telescope during 2005. For each photometric point we report the filter (column 1), the Modified Julian Date (MJD, column 2), the integration time in seconds (column 3), the flux density in mJy (column 4) and the correspondent standard deviation (column 5). (1 data file).

We report the outcome of a deep optical photometric survey of a 30×30 square arcmin area in the I... more We report the outcome of a deep optical photometric survey of a 30×30 square arcmin area in the IC 2391 young open cluster, complemented by IR photometry from the 2MASS catalogue and the Spitzer space telescope. The optical data were obtained by using the Wide-Field Imager (WFI) at the ESO 2.2m telescope; the photometric completeness limit of this survey at

We present the Gattini project: a multisite campaign to measure the optical sky properties above ... more We present the Gattini project: a multisite campaign to measure the optical sky properties above the two high altitude Antarctic astronomical sites of Dome C and Dome A. The Gattini-DomeC project, part of the IRAIT site testing campaign and ongoing since January 2006, consists of two cameras for the measurement of optical sky brightness, large area cloud cover and auroral detection above the DomeC site, home of the French-Italian Concordia station. The cameras are transit in nature and are virtually identical except for the nature of the lenses. The cameras have operated successfully throughout the past two Antarctic winter seasons and here we present the first results obtained from the returned 2006 dataset. The Gattini-DomeA project will place a similar site testing facility at the highest point on the Antarctic plateau, Dome A, with observations commencing in 2008. The project forms a small part of a much larger venture coordinated by the Polar Research Institute of China as part of the International Polar Year whereby an automated site testing facility called PLATO will be traversed into the DomeA site. The status of this exciting and ambitious project with regards to the Gattini-DomeA cameras will be presented.

ESA Special …, 2006

a n o 4 ,G . C u t i s p o t o 5 , I. Pagano 5 ,E .D i s t e f a n o 5 , P. R o m ano 5 ,R . A l ... more a n o 4 ,G . C u t i s p o t o 5 , I. Pagano 5 ,E .D i s t e f a n o 5 , P. R o m ano 5 ,R . A l o n s o 6 ,P . J . A m a d o 3 ,S .M a r t ın-Ruiz 3 ,M . R a i n e r 2 , K. Uytterhoeven 2,7 , C. Aerts 7 , E. Antonello 2 ,J . A .B e l m o n t e 6 , and M. Bossi 2 ,a n dG .H a n d l e r 8 ,A . M .H u b e r t 9 , E. Janot-Pacheco 10 ,Y . L e b r e t o n 9 , L. Mantegazza 2 , P. Mathias ABSTRACT A vast ground-based observational effort was launched several years ago in order to prepare the optimal selection of targets for the COROT seismology programme. The first objective of this ground-based programme was to characterize as completely as possible all potential targets of the mission, in particular to determine their effective temperature, surface gravity, metallicity, and projected rotation velocity. In order to achieve this goal, photometric and high resolution spectroscopic observations were obtained for more than 2,000 stars, and made available to the community via the Internet in the GAUDI database.

MEMORIE-SOCIETA ASTRONOMICA ITALIANA, 2007

... Istituto Nazionale di Astrofisica Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-9... more ... Istituto Nazionale di Astrofisica Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania, Italy e-mail: sergio.messina@oact.inaf.it ... Press periodograms as well the CLEAN al-gorithm are used to infer the rotation pe-riod (Scargle Scargle (1982); Horne &amp; Baliunas ...

Arxiv preprint arXiv: …, 2007

1 INAF Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate, Italy. e-mail: enn... more 1 INAF Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate, Italy. e-mail: ennio.poretti,monica.rainer,katrien.uytterhoeven@brera.inaf.it 2 INAF Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania, Italy. e-mail: gcutispoto,eds,prom@oact.inaf.it

AIP Conference …, 2009

The formation of low‐mass stars and brown dwarfs and their disks is a hot observational topic. Su... more The formation of low‐mass stars and brown dwarfs and their disks is a hot observational topic. Such studies also holds important keys for the clarification of the planet formation mechanism. Because of its proximity (150 pc) and young age (3050 Myr), the IC2391 ...

Astronomy and Astrophysics, 2007

Context. Spectral variability is the main tool for constraining emission models of BL Lac objects... more Context. Spectral variability is the main tool for constraining emission models of BL Lac objects. Aims. By means of systematic observations of the BL Lac prototype PKS 2155-304 in the infrared-optical band, we explore variability on scales of months, days, and hours. Methods. We made our observations with the robotic 60 cm telescope REM located at La Silla, Chile, and VRIJHK filters were used. Results. PKS 2155-304 was observed from May to December 2005. The wavelength interval explored, the total number of photometric points, and the short integration time render our photometry substantially superior to previous ones for this source. On the basis of the intensity and colour, we distinguish three different states of the source, each lasting months, which include all those described in the literature. In particular, we report the highest state ever detected in the H band. The source varied by a factor of 4 in this band, much more than in the V band (a factor ≈2). The source softened with increasing intensity, in contrast to the general pattern observed in the UV-X-ray bands. On five nights in November we had nearly continuous monitoring for 2-3 h. A variability episode on a time scale of τ ≈ 24 h is well-documented, and a much more rapid flare with τ = 1-2 h, is also apparent, but is supported by relatively few points.

Astronomy and Astrophysics, 2009

Aims. We report the outcome of a deep multiwavelength study of the IC 2391 young open cluster. We... more Aims. We report the outcome of a deep multiwavelength study of the IC 2391 young open cluster. We attempt to uncover new lowmass and sub-stellar members of the cluster and identify new debris disk objects. Methods. We observed a 30 × 30 square arcmin area in IC 2391 using the wide-field imager at the ESO 2.2 m telescope. The completeness limits of the photometry at the 3σ level are V = 24.7, R C = 23.7, and I C = 23.0, faint enough to reveal sub-stellar members down to ∼0.03 M . Our membership criteria are based on use of our optical data in combination with JHK S magnitudes from the 2MASS catalog. We also estimate the physical parameters of the selected candidates. Debris disk candidates are identified on the basis of their infrared excess emission using near-and mid-infrared photometry from the Spitzer Space Telescope. Results. Our optical survey, which has a limiting magnitude at the 3σ level 1-2 mag fainter than previous optical surveys conducted in IC 2391, revealed 29 new low-mass member candidates of the cluster. We estimate the contamination to be at least ∼50%. We constrain the fraction of sub-stellar objects in the range 8-15% and discuss possible explanations of the deficit of brown dwarfs in this cluster. We also identify 10 candidates in the cluster showing IR excess emission consistent with the presence of debris disks.

Astronomy & Astrophysics, 2009

We report the outcome of a deep multi-wavelength study of the IC2391 young open cluster. We aim a... more We report the outcome of a deep multi-wavelength study of the IC2391 young open cluster. We aim at uncovering new low-mass and sub-stellar members of the cluster and identifying new debris disk objects. A 30*30 square arcmin area in IC 2391 was observed using the wide-field imager at the ESO 2.2m telescope. The completeness limits of the photometry at 3 sigma level are V=24.7, Rc=23.7 and Ic=23.0, faint enough to reveal sub-stellar members down to about 0.03 solar masses. Our membership criteria are based on the use of our optical data, in combination with JHKs magnitudes from the 2MASS catalog. We also estimate the physical parameters of the selected candidates. Debris disk candidates are identified on the basis of their infrared excess emission using near- and mid-infrared photometry from the Spitzer Space Telescope. Our optical survey, which has a limiting magnitude at 3 sigma level 1-2 mag fainter than previous optical surveys conducted in IC2391, revealed 29 new low-mass member candidates of the cluster. We estimate the contamination to be at least 50%. We constrain the fraction of sub-stellar objects in the range 8-15% and discuss possible explanations for the deficit of brown dwarfs in this cluster. We also identified 10 candidates in the cluster showing IR excess emission consistent with the presence of debris disks.

Eas Publications Series, 2008

Beating the Earth's day-night cycle is mandatory for long and continuous time-series photometry a... more Beating the Earth's day-night cycle is mandatory for long and continuous time-series photometry and had been achieved with either large ground-based networks of observatories at different geographic longitudes or when conducted from space. A third possibility is offered by a polar location with astronomically-qualified site characteristics. Aims. In this paper, we present the first scientific stellar time-series optical photometry from Dome C in Antarctica and analyze approximately 13,000 CCD frames taken in July 2007. We conclude that high-precision CCD photometry with exceptional time coverage and cadence can be obtained at Dome C in Antarctica and be successfully used for time-series astrophysics.

Eas Publications Series, 2007

The huge amount of CCD photometric data collected by robotic telescopes (as for instance the ICE-... more The huge amount of CCD photometric data collected by robotic telescopes (as for instance the ICE-T telescope to be installed at Dome-C) requires a fully automated approach to the reduction and analysis procedures. To this end, we are developing a pipeline, making use of IRAF, DAOPHOTII and tasks build up by us, which will enable to automatically extract differential magnitude

Monthly Notices of the Royal Astronomical Society, 2009

Since 2004, we have been engaged in a long-term observing program to monitor young stellar object... more Since 2004, we have been engaged in a long-term observing program to monitor young stellar objects in the Orion Nebula Cluster. We have collected about two thousands frames in V, R, and I broad-band filters on more than two hundred nights distributed over five consecutive observing seasons. The high-quality and time-extended photometric data give us an opportunity to address various phenomena associated with young stars. The prime motivations of this project are i) to explore various manifestations of stellar magnetic activity in very young low-mass stars; ii) to search for new pre-main sequence eclipsing binaries; and iii) to look for any EXor and FUor like transient activities associated with YSOs. Since this is the first paper on this program, we give a detailed description of the science drivers, the observation and the data reduction strategies as well. In addition to these, we also present a large number of new periodic variables detected from our first five years of time-series photometric data. Our study reveals that about 72% of CTTS in our FoV are periodic, whereas, the percentage of periodic WTTS is just 32%. This indicates that inhomogeneities patterns on the surface of CTTS of the ONC stars are much more stable than on WTTS. From our multi-year monitoring campaign we found that the photometric surveys based on single-season are incapable of identifying all periodic variables. And any study on evolution of angular momentum based on single-season surveys must be carried out with caution.

The photometric observations of the ONC reported here, were obtained between 2004 January 18 and ... more The photometric observations of the ONC reported here, were obtained between 2004 January 18 and 2008 April 15, using the 2m Himalayan Chandra Telescope (HCT) and the 2.3m Vainu Bappu Telescope (VBT). (3 data files).

arXiv preprint arXiv:1011.3346, Nov 15, 2010

We present some preliminary results from our program of intensive near-infrared photometric monit... more We present some preliminary results from our program of intensive near-infrared photometric monitoring of a sample of confirmed and candidate Luminous Blue Variables (LBVs) conducted from 2008 to 2010. Clear long-term variability has been observed for Wray 17-96 and V481 Sct, with overall brightness variation greater than 1 mag in the J band. Other sources, such as LBV 1806-20 showed detectable variability with amplitudes of few tenths of a magnitude with time-scale of about 60 days.