Papers by Nicolas Epchtein
VizieR Online Data Catalog: Near IR Photometry of a Sample of IRAS Point Sources (Fouque+ 1992)
Infrared photometry of SN 1987A
Astronomy and Astrophysics, 1987
The authors present infrared (1 mum - 14 mum) photometric and spectroscopic observations of SN 19... more The authors present infrared (1 mum - 14 mum) photometric and spectroscopic observations of SN 1987A obtained at ESO La Silla between February 28 and March 16, 1987. A preliminary interpretation of the photometry suggests an expanding photosphere with Teff decreasing from 5800K on March 1, to 5200K on March 11; adopting a distance of 55 kpc, the luminosity increased
Symposium - International Astronomical Union, 1999
In the last 3 decades, infrared surveys have discovered new classes of AGB stars, and significant... more In the last 3 decades, infrared surveys have discovered new classes of AGB stars, and significantly improved our knowledge of their statistical and physical properties, often in conjunction with surveys in other spectral ranges (mainly OH maser lines). After a short description of the major past and present infrared surveys and their most commonly used analysis tools, their impact is illustrated by a few examples such as the characterisation of the populations of the Bulge and Magellanic Clouds and the distribution of carbon-rich stars in the galactic disc. In conclusion, further all-sky surveys in the still unexplored spectral regions between 2 and 10 μm are strongly advocated as well as the development of ground-based telescopes dedicated to deeper surveys and monitoring of the variability.
Exploring the infrared stellar populations of the Galaxy with DENIS first results of star counts
AIP Conference Proceedings, 1996
Exploring the infrared stellar populations of the Galaxy with DENIS first results of star counts.... more Exploring the infrared stellar populations of the Galaxy with DENIS first results of star counts. [AIP Conference Proceedings 348, 81 (1996)]. Stéphanie Ruphy, Nicolas Epchtein. Abstract. The DENIS project (Deep Near Infrared ...
New detections of probable massive pre-main sequence stars in the southern galactic plane
Astronomy and Astrophysics
ABSTRACT
Galactic Science with DENIS and 2MASS (invited talk)
Infrared monitoring of the sky background emission above Dome C
ABSTRACT
New CO and HCN sources associated with IRAS carbon stars
Astronomy & Astrophysics, 1987
An unbiased sample of 53 unidentified IRAS carbon stars, based on the 12 mum flux and SiC feature... more An unbiased sample of 53 unidentified IRAS carbon stars, based on the 12 mum flux and SiC feature contrast, was searched for CO (J = 1-0), HCN (J = 1-0) and SiC2 (505 - 404) lines. Broad CO and/or HCN lines (>=17 km s-1) were detected in 22 objects, indicating that they are evolved stars. Narrow CO lines were also
Astrophysics and Space Science Library, 1998
The Impact of Near-Infrared Sky Surveys on Galactic and Extragalactic Astronomy
Astrophysics and Space Science Library, 1998
I. Infrared Survey Status. The Deep Near Infrared Survey of the Southern Sky: Progress Report and... more I. Infrared Survey Status. The Deep Near Infrared Survey of the Southern Sky: Progress Report and Scientific Results Overview N. Epchtein. The Two Micron All-Sky Survey (2MASS): Status Report November 1997 M. Skrutskie. Midcourse Space Experiment Surveys S. Price, et al. II: Galactic Structure. The Impact of IR Surveys on Galactic Structure O. Bienayme. Resolved DENIS and UKIRT Infrared Stellar Observations Towards the Galactic Center M. Unavane, G. Gilmore. Mass-Lossing AGB Stars and Young Stars in the ISOGAL Survey A. Omont, et al. Galactic Bulge from TMGS Star Counts M. Lopez-Corredoira, et al. IR Star Counts in the Inner Disc P.L. Hammersley, et al. Spatial Distribution of Evolved Giant Stars in the Galactic Disc Using DENIS Data S. Ruphy. III: Stars. Infrared Emission of Carbon Stars M.A.T. Groenewegen. AGB Stars in the Galactic Bulge Observed by DENIS M. Schultheis, et al. Analysis of DENIS Data in ISOGAL Fields C. Alard. In Quest of Very Low Mass Stars and Brown Dwarfs with Near-IR Surveys T. Forveille, et al. Searching for Low-Mass Stars and Brown Dwarfs with 2MASS J.D. Kirkpatrick, et al. DENIS Survey of AGB and Tip-RGB Stars in the LMC Bar West and the Optical Center Fields C. Loup, et al. DENIS and HIPPARCOS: Luminosity and Kinematic Calibrations R. Alvarez, M.-O. Mennessier. Maximum Likelihood Estimation of the Scale Height of Mira Variables Z. Berend, L.J. Balazs. IV: Star Forming Regions and Interstellar Medium. 2MASS Observations of Molecular Clouds J.M. Carpenter. Star Forming Regions and Near-Infrared Surveys T. Montmerle. A Study of Extinction and Star Formation in the Chameleon I Cloud with DENIS L. Cambresy. DENIS and ISOCAM Observations of ChamI Cloud P. Persi, et al. Planetary Nebulae with DENIS S. Kimeswenger. V: Extragalactic. Galaxies with DENIS G.A. Mamon, et al. Extragalactic Astronomy with 2MASS S.E. Schneider, et al. Large-Scale Structure Behind the Milky Way from Near-IR Surveys R.C. Kraan-Korteweg, et al. Rapid Extraction of Galaxies from DENIS G. Paturel, et al. Wide-Angle Near-Infrared Surveys of Local Galaxies B. Mobasher. Detection of Low Surface Brightness Galaxies in 2MASS T. Jarrett. 2MASS and the Tully-Fisher Relation J.L. Rosenberg. QSOs in the 2-Micron All-Sky Survey R. Cutri, et al. The First-VLA Survey: The First 5000 Square Degrees R. Becker. FIRST-VLA Radiosources in ELAIS Areas E.A. Gonzalez-Solares, et al. VI: Miscellaneous. The SOM-Fitting Method E. Bertin. Near-Infrared Observations of Asteroids A. Baudrand, et al.
Astrophysics and Space Science Library, 1997
Astrophysics and Space Science Library, 1997
Large infrared survey telescope for Antarctica at Dome C
SPIE Proceedings, 2002
The first results obtained from the Site Campaigns performed in the last years in different locat... more The first results obtained from the Site Campaigns performed in the last years in different locations of the Antarctic Continent and the acquired experience obtained from the first astronomical IR measures with SPIREX, have in fact opened the way to a present time challenge, about the installation of a large IR Telescope in the best possible site on earth, that will be competitive with the present frontier of ground based and space telescopes in the Infrared range. A project in this context has been submitted to the Italian Plan for Antarctic Research (PNRA), in collaboration with French and Australian colleagues that began to be funded this year. The project entitled "A preliminary study for a Large Infrared Telescope at Dome C", will lay the bases for the realization of a non-conventional instrument for the mid-IR domain, suited for the very particular and severe Antarctic situation. In this first paper a general overview is done about the future development plan for the GTA (Grande Telescopio Antartico), paying attention to the following themes: Large aperture and low emissivity and high reliability of Antarctic IR telescopes High resolution and very high sensitivity objectives for a mid-ir Survey Telescope. Non-conventional observing modes for quasi drift-scan measurements.
LEDA galaxies with DENIS measurements catalog (Paturel+, 2005)
The catalog is sorted according to the field 1 (right ascension and declination for 2000). There ... more The catalog is sorted according to the field 1 (right ascension and declination for 2000). There are 753153 lines of 359 characters each. Unknown values are either 0.00 (or 9.99 if 0.00 is allowed) (1 data file).
2MASS Extragalactic Studies: Early Results from the Prototype Camera
Astrophysics and Space Science Library, 1997
... Binggeli, B., Sandage, A., & Tammann, GA 1985, AJ, 90, 1681 Caldwell, N., Rose, JA, Sharp... more ... Binggeli, B., Sandage, A., & Tammann, GA 1985, AJ, 90, 1681 Caldwell, N., Rose, JA, Sharples, RM, Ellis, RS, & Boser, RG 1993, AJ, 106, 473 Chester, TJ, & Jarrett, T. 1995, 2nd DENIS Euroconference Colless, M., & Dunn, AM 1996, ApJ, 458, 435 Kent, SM, & Gunn, JE 1982 ...
Proceedings of the International Astronomical Union, 2012
The Polar Large Telescope (PLT) project is primarily aimed at undertaking large, wide band synopt... more The Polar Large Telescope (PLT) project is primarily aimed at undertaking large, wide band synoptic astronomical surveys in the infrared in order to provide critical data to the forthcoming generation of observational facilities such as ALMA, JWST, LSST and the E–ELT, and to complement the observations obtained with them. Sensitive thermal IR surveys beyond 2.3 μm cannot be carried out from any existing ground based observatory and the Antarctic Plateau is the only place on the ground where it can be envisaged, thanks to its unique atmospheric and environmental properties, such as the turbulence profile (image quality), the low opacity and the reduced thermal background emission of the sky. These unique conditions enable high angular resolution wide field surveys in the near thermal infrared (2.3–5 μm). This spectral range is particularly well suited to tackling key astrophysical questions such as: i) investigating the nature of the distant universe, the first generation of stars an...
The Astrophysical Journal, 2010
We used Spitzer infrared observations to find the young stars of two H ii regions in the Large Ma... more We used Spitzer infrared observations to find the young stars of two H ii regions in the Large Magellanic Cloud, N63 and N180. The young stellar object (YSO) candidates were identified in each nebula by means of color-color, color-magnitude diagrams, and the shapes of their spectral energy distributions (SEDs). The most luminous YSOs are found near the ionization fronts within strong 8 m emission clumps. Most YSOs, less luminous, are seen in projection inside the H ii regions. HST images show several Class I stars that have emerged along the borders of the H ii regions; other YSOs are embedded in cometary clouds. The most luminous YSO of N63 is connected to a string of pointlike sources. Its SED can be modeled by a central source of stellar mass M ? between 7 and 11 M , with a circumstellar disk of outer radius R d of $55 AU, and an envelope of moderate accretion rate, Ṁenv of $2 ; 10 À5 M yr À1 . N180 is experiencing a phase of star formation more intense than N63, attested by the properties of its most luminous YSO: M ? of 25 M , R d of $200 AU, and Ṁenv of $1:5 ; 10 À3 M yr À1 . The modes of triggered star formation in N63 and N180 appear similar to those seen in Galactic H ii regions.
Astronomy and …, 1998
We present JHKL photometry of a sample of 150 IRAS stars in the third and fourth galactic quadran... more We present JHKL photometry of a sample of 150 IRAS stars in the third and fourth galactic quadrant with |b| <2 • selected according to their IRAS colour (0.160≤[12-25]≤1.156). We identify 27 carbon star candidates using the [12-25] vs. K-L two-colour diagram method. Among them, 10 are listed in the Stephenson's catalogue of carbon stars and 17 are new infrared carbon stars (IRCS) candidates. Their distances are found to be larger than 3 kpc. These data are combined with previous data to study the space distribution of IRCS. The number density seems to be independent of the galactocentric distance (R) toward the Galactic Center and to decrease exponentially toward the anticenter. At the present stage, it is not possible to disentangle effects such as incompleteness of the sample, different space distribution law and dependence of the luminosity on metallicity. In particular, we suggest that the apparent scarcity of IRCS in the central direction of the Galaxy (R<5 kpc) might be due to a selection effect. From the available data, we have found no IRCS within 1 kpc of the Galactic Center.
Astronomy and Astrophysics, 2001
We define a sample designed to select low-mass T Tauri stars and young brown dwarfs using DENIS d... more We define a sample designed to select low-mass T Tauri stars and young brown dwarfs using DENIS data in the Chamaeleon II molecular cloud. We use a star count method to construct an extinction map of the Chamaeleon II cloud. We select our low-mass T Tauri star and young brown dwarf candidates by their strong infrared color excess in the I -J/J -Ks color-color dereddened diagram. We retain only objects with colors I -J ≥ 2, and spatially distributed in groups around the cloud cores. This provides a sample of 70 stars of which 4 are previously known T Tauri stars. We have carefully checked the reliability of all these objects by visual inspection of the DENIS images. Thanks to the association of the optical I band to the infra-red J and Ks bands in DENIS, we can apply this selection method to all star formation regions observed in the southern hemisphere. We also identify six DENIS sources with X-ray sources detected by ROSAT. Assuming that they are reliable low-mass candidates and using the evolutionary models for low-mass stars, we estimate the age of these sources between 1 Myr and <10 Myr.
Astronomy & Astrophysics, 2003
This paper reports updated results on our systematic mining of the DENIS database for nearby very... more This paper reports updated results on our systematic mining of the DENIS database for nearby very cool M-dwarfs (M 6V-M 8V, 2.0 ≤ I -J ≤ 3.0, photometric distance within 30 pc), initiated by Phan-Bao et al. (2001, hereafter Paper I). We use M dwarfs with well measured parallaxes (HIP, GCTP, ...) to calibrate the DENIS (M I , I -J) colour-luminosity relationship. The resulting distance error for single dwarfs is about 25%. Proper motions, as well as B and R magnitudes, were measured on archive Schmidt plates for those stars in the DENIS database that meet the photometric selection criteria. We then eliminate the giants by a Reduced Proper Motion cutoff, which is significantly more selective than a simple proper motion cutoff. It greatly reduces the selection bias against low tangential velocity stars, and results in a nearly complete sample. Here we present new data for 62 red dwarf candidates selected over 5700 square degrees in the DENIS database. 26 of those originate in the 2100 square degrees analysed in Paper I, with improved parameters here, and 36 were found in 3600 additional square degrees. 25 of those are new nearby dwarfs. We determine from that sample of 62 stars a stellar density for 12.0 ≤ M I ≤ 14.0 of Φ I cor = (2.2 ± 0.4) × 10 -3 stars pc -3 mag -1 . This value is consistent with photometric luminosity functions measured from deeper and smaller-field observations, but not with the nearby star luminosity function. In addition we cross-identified the NLTT and DENIS catalogues to find 15 similar stars, in parts of the sky not yet covered by the colour-selected search. We present distance and luminosity estimates for these 15 stars, 10 of which are newly recognized nearby dwarfs. A similar search in Paper I produced 4 red dwarf candidates, and we have thus up to now identified a total of 35 new nearby late-M dwarfs.
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Papers by Nicolas Epchtein