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38
Jul 20, 2013
07/13
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P. Leisy; M. Dennefeld
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We present the second part of an optical spectroscopic study of planetary nebulae in the LMC and SMC. The first paper, Leisy & Dennefeld (1996), discussed the CNO cycle for those objects where C abundances were available. In this paper we concentrate more on other elemental abundances (such as O, Ne, S, Ar) and their implications for the evolution of the progenitor stars. We use a much larger sample of 183 objects, of which 65 are from our own observations, where the abundances have been...
Source: http://arxiv.org/abs/astro-ph/0609408v1
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42
Jul 20, 2013
07/13
by
C. Chevalier; S. A. Ilovaisky; P. Leisy; F. Patat
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eye 42
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Direct I and V-band imaging of Aql X-1 in quiescence and during outburst maximum shows that the true optical counterpart is the interloper located 0.48" West of the previously known star. We find for the new counterpart V = 21.6 and V-I = 2.2 in quiescence, when its contribution to the total light was 12% in V and 22% in I. Analysis of this photometry and of low-resolution spectra of the sum of both stars, also taken during quiescence, shows that the likely spectral types for the...
Source: http://arxiv.org/abs/astro-ph/9906278v1
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34
Sep 18, 2013
09/13
by
D. R. Goncalves; L. Magrini; P. Leisy; R. M. L. Corradi
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eye 34
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We report the results of spectroscopic observations, obtained with the GEMINI Multi-Object Spectrograph, of 8 planetary nebulae (PNe) in the dwarf spheroidal (dSph) galaxy NGC147, a companion of M31. The physico-chemical properties of the six brightest PNe (Corradi et al. 2005) were derived using both the empirical ICF method and photoionization modelling with CLOUDY. Different aspects of the evolution of low and intermediate mass stars in a low-metallicity environment are analysed using...
Source: http://arxiv.org/abs/astro-ph/0611756v1
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30
Sep 23, 2013
09/13
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S. Carpano; B. Altieri; A. R. King; A. Nucita; P. Leisy
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Aims. We report the discovery of a peculiar object observed serendipitously with XMM-Newton. We present its timing and spectral properties and investigate its optical counterpart. Methods. The light curve of the X-ray source, its spectrum, and the spectrum of the best optical counterpart are presented and analyzed. Results. The X-ray flux decreases by a factor of 6.5 within 1 h and stays in a low state for at least 10 h, thereby suggesting the presence of an eclipse. The spectrum is very soft,...
Source: http://arxiv.org/abs/0801.4246v1
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52
Sep 18, 2013
09/13
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L. Magrini; J. M. Vilchez; A. Mampaso; R. L. M. Corradi; P. Leisy
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We present spectroscopic observations of a sample of 72 emission-line objects, including mainly HII regions, in the spiral galaxy M 33. Spectra were obtained with the multi-object, wide field spectrograph AF2/WYFFOS at the 4.2m WHT telescope. Line intensities, extinction, and electron density were determined for the whole sample of objects. The aim of the present work was to derive chemical and physical parameters of a set of HII regions, and from them the metallicity gradient. Electron...
Source: http://arxiv.org/abs/0705.3116v1
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37
Sep 22, 2013
09/13
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L. Magrini; R. L. M. Corradi; P. Leisy; A. Scatarzi; L. Morbidelli; M. Perinotto
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We have analyzed the behaviour of various parameters of PNe in the Magellanic Clouds (MCs) and the Galaxy as a function of their morphology. The luminosity function of different morphological types has been built, finding that elliptical and round PNe dominate the bright cutoff both in the MCs and in the Galaxy. The dependence of the [OIII] absolute magnitude on chemical abundances has been investigated.
Source: http://arxiv.org/abs/astro-ph/0310129v1
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80
Sep 18, 2013
09/13
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J. P. Beaulieu; W. J. de Wit; H. J. G. M. L. Lamers; J. B. Marquette; C. Coutures; P. Leisy; S. Totor; N. Palanque-Delabrouille; EROS2 collaboration
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Using data from the EROS2 microlensing survey, we report the discovery of two blue objects with irregular photometric behaviour of $\Delta V \sim 0.1$-0.4 mag on time scales of 20 to 200 days. They show a bluer when fainter behaviour. Subsequent spectra taken with the ESO 3.6m telescope show spectral type B4eIII and B2eIV-V with strong $H \alpha$ emission. These objects resemble the Herbig AeBe but also classical Be stars. At this stage, it is not possible to distinguish unambiguously between...
Source: http://arxiv.org/abs/astro-ph/0110166v1
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45
Sep 18, 2013
09/13
by
L. Magrini; R. L. M. Corradi; R. Greimel; P. Leisy; A. Mampaso; M. Perinotto; J. R. Walsh; N. A. Walton; A. A. Zijlstra; D. Minniti; M. Mora
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In the framework of the Local Group Census (LGC), a survey of the Local Group (LG) galaxies above Dec=$-30^\circ$, which is aimed at surveying their populations with strong emission lines, we have searched for planetary nebulae (PNe) in the low-metallicity dwarf irregular galaxies IC1613, WLM, GR8. Two new candidate PNe have been found in IC1613, one in WLM and none in GR8. The observations presented in this paper, together with the previous results from the LGC, represent the first step in the...
Source: http://arxiv.org/abs/astro-ph/0505343v1
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39
Sep 17, 2013
09/13
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L. Magrini; R. L. M. Corradi; R. Greimel; P. Leisy; D. J. Lennon; A. Mampaso; M. Perinotto; D. L. Pollacco; J. R. Walsh; N. A. Walton; A. A. Zijlstra
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eye 39
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In the framework of our narrow-band survey of the Local Group galaxies, we present the results of the search for planetary nebulae (PNe) in the dwarf irregular galaxies IC10, LeoA and SextansA. Using the standard on-band/off-band technique, sixteen new candidate PNe have been discovered in the closest starburst galaxy, IC10. The optical size of this galaxy is estimated to be much larger than previously thought, considering the location of the new PNe in an area of 3.6 kpc X 2.7 kpc. We also...
Source: http://arxiv.org/abs/astro-ph/0305105v1
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53
Sep 20, 2013
09/13
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A. Mampaso; R. L. M. Corradi; K. Viironen; P. Leisy; R. Greimel; J. E. Drew; M. J. Barlow; D. J. Frew; J. Irwin; R. A. H. Morris; Q. A. Parker; S. Phillipps; E. R. Rodriguez-Flores; A. A. Zijlstra
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eye 53
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The Isaac Newton Telescope Photometric H-alpha Survey (IPHAS) is currently mapping the Northern Galactic plane reaching to r'=20 mag with typically 1" resolution. Hundreds of Planetary Nebulae (PNe), both point-like and resolved, are expected to be discovered. We report on the discovery of the first new PN from this survey: it is an unusual object located at a large galactocentric distance and has a very low oxygen abundance. The nebula shows an intricate morphology: there is an inner ring...
Source: http://arxiv.org/abs/astro-ph/0608108v1
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42
Sep 23, 2013
09/13
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M. -R. L. Cioni; K. Bekki; G. Clementini; W. J. G. de Blok; J. P. Emerson; C. J. Evans; R. de Grijs; B. K. Gibson; L. Girardi; M. A. T. Groenewegen; V. D. Ivanov; P. Leisy; M. Marconi; C. Mastropietro; B. Moore; T. Naylor; J. M. Oliveira; V. Ripepi; J. Th. van Loon; M. I. Wilkinson; P. R. Wood
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eye 42
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The Magellanic System represents one of the best places to study the formation and evolution of galaxies. Photometric surveys of various depths, areas and wavelengths have had a significant impact on our understanding of the system; however, a complete picture is still lacking. VMC (the VISTA near-infrared YJKs survey of the Magellanic System) will provide new data to derive the spatially resolved star formation history and to construct a three-dimensional map of the system. These data combined...
Source: http://arxiv.org/abs/0710.3706v2
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52
Sep 21, 2013
09/13
by
E. A. Gonzalez-Solares; N. A. Walton; R. Greimel; J. E. Drew; M. J. Irwin; S. E. Sale; K. Andrews; A. Aungwerojwit; M. J. Barlow; E. van den Besselaar; R. L. M. Corradi; B. T. Gaensicke; P. J. Groot; A. S. Hales; E. C. Hopewell; H. Hu; J. Irwin; C. Knigge; E. Lagadec; P. Leisy; J. R. Lewis; A. Mampaso; M. Matsuura; B. Moont; L. Morales-Rueda; R. A. H. Morris; T. Naylor; Q. A. Parker; P. Prema; S. Pyrzas; G. T. Rixon; P. Rodriguez-Gil; G. Roelofs; L. Sabin; I. Skillen; J. Suso; R. Tata; K. Viironen; J. S. Vink; A. Witham; N. J. Wright; A. A. Zijlstra; A. Zurita; J. Drake; J. Fabregat; D. J. Lennon; P. W. Lucas; E. L. Martin; D. Steeghs; Y. C. Unruh
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The INT/WFC Photometric H-alpha Survey of the Northern Galactic Plane (IPHAS) is an imaging survey being carried out in H-alpha, r' and i' filters, with the Wide Field Camera (WFC) on the 2.5-metre Isaac Newton Telescope (INT) to a depth of r'=20 (10 sigma). The survey is aimed at revealing large scale structure in our local galaxy, and also the properties of key early and late populations making up the Milky Way. Mapping emission line objects enables a particular focus on objects in the young...
Source: http://arxiv.org/abs/0712.0384v2
