References of "Morel, Thierry"
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See detailThe European Large Area ISO Survey - VIII. 90-microns final analysis and source counts
Heraudeau, P.; Oliver, S.; del Burgo, C. et al

in Monthly Notices of the Royal Astronomical Society (2004), 354

We present a re-analysis of the European Large Area Infrared Space Observatory (ISO) Survey (ELAIS) 90-μm observations carried out with ISOPHOT, an instrument on board the ISO of the European Space ... [more ▼]

We present a re-analysis of the European Large Area Infrared Space Observatory (ISO) Survey (ELAIS) 90-μm observations carried out with ISOPHOT, an instrument on board the ISO of the European Space Agency. With more than 12 deg[SUP]2[/SUP], the ELAIS survey is the largest area covered by ISO in a single programme and is about one order of magnitude deeper than the IRAS 100-μm survey. The data analysis is presented and was mainly performed with the PHOT interactive analysis software but using the pairwise method of Stickel et al. for signal processing from edited raw data to signal per chopper plateau. The ELAIS 90-μm catalogue contains 237 reliable sources with fluxes larger than 70 mJy and is available in the electronic version of this article. Number counts are presented and show an excess above the no-evolution model prediction. This confirms the strong evolution detected at shorter (15 μm) and longer (170 μm) wavelengths in other ISO surveys. The ELAIS counts are in agreement with previous works at 90 μm and in particular with the deeper counts extracted from the Lockman hole observations. Comparison with recent evolutionary models show that the models of Franceschini et al. and Guiderdoni et al. (which includes a heavily extinguished population of galaxies) give the best fit to the data. Deeper observations are nevertheless required to discriminate better between the model predictions in the far-infrared, and are scheduled with the Spitzer Space Telescope, which has already started operating, and will also be performed by ASTRO-F. [less ▲]

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See detailHydrogen in the atmosphere of the evolved WN3 Wolf-Rayet star WR 3: defying an evolutionary paradigm?
Marchenko, S. V.; Moffat, A. F. J.; Crowther, P. A. et al

in Monthly Notices of the Royal Astronomical Society (2004), 353(1), 153-161

WR 3 is the brightest very early-type WN star in the sky. Based on several years of time-resolved spectroscopy and precision photometry on various time-scales, we deduce that WR 3 is most likely a single ... [more ▼]

WR 3 is the brightest very early-type WN star in the sky. Based on several years of time-resolved spectroscopy and precision photometry on various time-scales, we deduce that WR 3 is most likely a single, weak-lined star of type WN3ha (contrary to its current catalogue-type of WN3 + O4), with H lines occurring both in emission and absorption in its wind. This conclusion is confirmed and strengthened via detailed modelling of the spectrum of WR 3. Given the similarity of WR 3 with numerous H-rich WNE stars in the Large Magellanic Cloud and especially the Small Magellanic Cloud, and its location towards the metal-deficient exterior of the Galaxy, we conclude that rotationally induced meridional circulation probably led to the apparently unusual formation of this hot Galactic WN star with enhanced hydrogen. Although we cannot completely rule out the possibility of a binary with a low orbital inclination and/or long period, we regard this latter possibility as highly unlikely. [less ▲]

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See detailOn the determination of oxygen abundances in chromospherically active stars
Morel, Thierry ULg; Micela, G.

in Astronomy and Astrophysics (2004), 423

We discuss oxygen abundances derived from [O I] λ6300s and the O I triplet in stars spanning a wide range in chromospheric activity level, and show that these two indicators yield increasingly discrepant ... [more ▼]

We discuss oxygen abundances derived from [O I] λ6300s and the O I triplet in stars spanning a wide range in chromospheric activity level, and show that these two indicators yield increasingly discrepant results with higher chromospheric/coronal activity measures. While the forbidden and permitted lines give fairly consistent results for solar-type disk dwarfs, spuriously high O I triplet abundances are observed in young Hyades and Pleiades stars, as well as in individual components of RS CVn binaries (up to 1.8 dex). The distinct behaviour of the [O I]-based abundances which consistently remain near-solar suggests that this phenomenon mostly results from large departures from LTE affecting the O I triplet at high activity level that are currently unaccounted for, but also possibly from a failure to adequately model the atmospheres of K-type stars. These results suggest that some caution should be exercised when interpreting oxygen abundances in active binaries or young open cluster stars. Based on observations collected at the European Southern Observatory, Chile (Proposals 64.L-0249 and 071.D-0260). Table \ref{tab_data} is only available in electronic form at http://www.edpsciences.org [less ▲]

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See detailThe European Large-Area ISO Survey (ELAIS): the final band-merged catalogue
Rowan-Robinson, M.; Lari, C.; Perez-Fournon, I. et al

in Monthly Notices of the Royal Astronomical Society (2004), 351

We present the final band-merged European Large-Area ISO Survey (ELAIS) Catalogue at 6.7, 15, 90 and 175 μm, and the associated data at U, g', r', i', Z, J, H, K and 20 cm. The origin of the survey ... [more ▼]

We present the final band-merged European Large-Area ISO Survey (ELAIS) Catalogue at 6.7, 15, 90 and 175 μm, and the associated data at U, g', r', i', Z, J, H, K and 20 cm. The origin of the survey, infrared and radio observations, data-reduction and optical identifications are briefly reviewed, and a summary of the area covered and the completeness limit for each infrared band is given. A detailed discussion of the band-merging and optical association strategy is given. The total Catalogue consists of 3762 sources. 23 per cent of the 15-μm sources and 75 per cent of the 6.7-μm sources are stars. For extragalactic sources observed in three or more infrared bands, colour-colour diagrams are presented and discussed in terms of the contributing infrared populations. Spectral energy distributions (SEDs) are shown for selected sources and compared with cirrus, M82 and Arp220 starburst, and active galactic nuclei (AGN) dust torus models. Spectroscopic redshifts are tabulated, where available. For the N1 and N2 areas, the Isaac Newton Telescope ugriz Wide Field Survey permits photometric redshifts to be estimated for galaxies and quasars. These agree well with the spectroscopic redshifts, within the uncertainty of the photometric method [~10 per cent in (1 +z) for galaxies]. The redshift distribution is given for selected ELAIS bands and colour-redshift diagrams are discussed. There is a high proportion of ultraluminous infrared galaxies (log[SUB]10[/SUB] of 1-1000 μm luminosity L[SUB]ir[/SUB] > 12.22) in the ELAIS Catalogue (14 per cent of 15-μm galaxies with known z), many with Arp220-like SEDs. 10 per cent of the 15-μm sources are genuine optically blank fields to r'= 24: these must have very high infrared-to-optical ratios and probably have z > 0.6, so are high-luminosity dusty starbursts or Type 2 AGN. Nine hyperluminous infrared galaxies (L[SUB]ir[/SUB] > 13.22) and nine extremely red objects (EROs) (r-K > 6) are found in the survey. The latter are interpreted as ultraluminous dusty infrared galaxies at z~ 1. The large numbers of ultraluminous galaxies imply very strong evolution in the star formation rate between z= 0 and 1. There is also a surprisingly large population of luminous (L[SUB]ir[/SUB] > 11.5), cool (cirrus-type SEDs) galaxies, with L[SUB]ir[/SUB]-L[SUB]opt[/SUB] > 0, implying A[SUB]V[/SUB] > 1. [less ▲]

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See detailLarge-scale wind structures in OB supergiants: a search for rotationally modulated Halpha variability
Morel, Thierry ULg; Marchenko, S. V.; Pati, A. K. et al

in Monthly Notices of the Royal Astronomical Society (2004), 351

We present the results of a long-term monitoring campaign of the Hα line in a sample of bright OB supergiants (O7.5-B9) which aims at detecting rotationally modulated changes potentially related to the ... [more ▼]

We present the results of a long-term monitoring campaign of the Hα line in a sample of bright OB supergiants (O7.5-B9) which aims at detecting rotationally modulated changes potentially related to the existence of large-scale wind structures. A total of 22 objects were monitored during 36 nights spread over six months in 2001-2002. Coordinated broad-band photometric observations were also obtained for some targets. Conspicuous evidence for variability in Hα is found for the stars displaying a feature contaminated by wind emission. Most changes take place on a daily time-scale, although hourly variations are also occasionally detected. Convincing evidence for a cyclical pattern of variability in Hα has been found in two stars: HD 14134 and HD 42087. Periodic signals are also detected in other stars, but independent confirmation is required. Rotational modulation is suggested from the similarity between the observed recurrence time-scales (in the range 13-25 d) and estimated periods of stellar rotation. We call attention to the atypical case of HD 14134, which exhibits a clear 12.8-d periodicity, both in the photometric and in the spectroscopic data sets. This places this object among a handful of early-type stars where one may observe a clear link between extended wind structures and photospheric disturbances. Further modelling may test the hypothesis that azimuthally-extended wind streams are responsible for the patterns of spectral variability in our target stars. [less ▲]

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See detailA Search for Rotationally Modulated Halpha Variability in OB Supergiants
Morel, Thierry ULg; Marchenko, S. V.; Pati, A. K. et al

in Stellar Rotation (2004, June 01)

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See detailThe near-IR counterpart to the high-mass X-ray binary X1908+075
Morel, Thierry ULg; Grosdidier, Y.

in The Astronomer's Telegram (2004), 291

<html> We report the near-IR identification of the likely counterpart to X1908+075, a highly-absorbed Galactic X-ray source recently suspected to belong to the rare class of OB supergiant-neutron star ... [more ▼]

<html> We report the near-IR identification of the likely counterpart to X1908+075, a highly-absorbed Galactic X-ray source recently suspected to belong to the rare class of OB supergiant-neutron star binary systems (Wen et al. 2000, ApJ, 532, 1119; Levine et al. 2004, ApJ, submitted, astro-ph/0404428). The <em>Einstein</em> and <em>HEAO 1</em> satellites have localized this X-ray source with an uncertainty of about 50''. [less ▲]

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See detailThe Photospheric Abundances of Active Binaries: First Results
Morel, Thierry ULg; Micela, G.; Favata, F. et al

in Stars as Suns : Activity, Evolution and Planets (2004, January 01)

The coronal abundances of chromospherically active binaries have come under close scrutiny in recent years thanks to several X-ray satellites such as XMM or Chandra. Unfortunately a detailed analysis of ... [more ▼]

The coronal abundances of chromospherically active binaries have come under close scrutiny in recent years thanks to several X-ray satellites such as XMM or Chandra. Unfortunately a detailed analysis of the chemical fractionation processes that are possibly operating between the photosphere and the corona is plagued by the lack of reliable and accurate photospheric abundance determinations. In particular a detailed investigation of the photospheric metal content seems worthwhile in the light of several studies that have questioned the customary use of photometric indices as effective temperature indicators in active binaries. We shall present our ongoing effort to determine in a self-consistent way accurate physical parameters and photospheric abundances for a large number of systems and discuss the implications of our results on their abundance patterns and evolutionary status. Preliminary results suggest that these systems are not as iron-deficient as found in previous studies and indicate an overabundance of several key elements (e.g. Na Mg Al Ca) with respect to the solar pattern. [less ▲]

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See detailThe photospheric abundances of active binaries. II. Atmospheric parameters and abundance patterns for 6 single-lined RS CVn systems
Morel, Thierry ULg; Micela, G.; Favata, F. et al

in Astronomy and Astrophysics (2003), 412

Photospheric parameters and abundances are presented for a sample of single-lined chromospherically active binaries from a differential LTE analysis of high-resolution spectra. Abundances have been ... [more ▼]

Photospheric parameters and abundances are presented for a sample of single-lined chromospherically active binaries from a differential LTE analysis of high-resolution spectra. Abundances have been derived for 13 chemical species, including several key elements such as Li, Mg, and Ca. Two methods have been used. The effective temperatures, surface gravities and microturbulent velocities were first derived from a fully self-consistent analysis of the spectra, whereby the temperature is determined from the excitation equilibrium of the Fe I lines. The second approach relies on temperatures derived from the (B-V) colour index. These two methods give broadly consistent results for the stars in our sample, suggesting that the neutral iron lines are formed under conditions close to LTE. We discuss the reliability in the context of chromospherically active stars of various colour indices used as temperature indicators, and conclude that the (V-R) and (V-I) colours are likely to be significantly affected by activity processes. Irrespective of the method used, our results indicate that the X-ray active binaries studied are not as metal poor as previously claimed, but are at most mildly iron-depleted relative to the Sun (-0.41protect <~ [Fe/H]protect la +0.11). A significant overabundance of several chemical species is observed (e.g., the alpha -synthezised elements). These abundance patterns are discussed in relation to stellar activity. Based on observations collected at ESO (La Silla, Chile). Table A.1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/412/495 [less ▲]

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See detailLarge-Scale Structures in OB Supergiants: from an Inhomogeneous Surface to a Structured Wind
Morel, Thierry ULg; Marchenko, S. V.; Pati, A. K. et al

in Bulletin of the American Astronomical Society (2003, May 01)

In 2000-2001 we performed long-term spectroscopic monitoring of a sample of bright OB-supergiants aimed at establishing the incidence of co-rotating, large-scale wind structures. In the optical, this can ... [more ▼]

In 2000-2001 we performed long-term spectroscopic monitoring of a sample of bright OB-supergiants aimed at establishing the incidence of co-rotating, large-scale wind structures. In the optical, this can be achieved by detecting rotationally modulated variability in Hα . Practically all the surveyed stars show dramatic line-profile variations operating on a daily (and in some cases on a hourly) timescale. Here we discuss the case of HD 14134 (B3 Ia) where a periodic modulation seen in the optical continuum (stellar surface, P=12.825d) triggers spectacular variations in the Hα emission line (stellar wind). [less ▲]

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See detailLarge-scale Wind Structures in OB Supergiants: a Search for Rotationally Modulated Halpha variability
Morel, Thierry ULg; Marchenko, S. V.; Pati, A. K. et al

in Bulletin of the Astronomical Society of India (2003), 31

We present preliminary results of a long-term spectroscopic monitoring of a sample of bright OB-supergiants aimed at establishing the incidence of co-rotating, large-scale wind structures by detecting ... [more ▼]

We present preliminary results of a long-term spectroscopic monitoring of a sample of bright OB-supergiants aimed at establishing the incidence of co-rotating, large-scale wind structures by detecting rotationally modulated variability in H. Dramatic line-profile variations operating on a daily (and in some cases on a hourly) timescale are observed. A detailed period analysis has been so far carried out for 2 stars, and revealed in both cases the existence of cyclical H variations consistent with rotational modulation. In the case of HD 14134, the same periodicity is found in the contemporaneous light curve. [less ▲]

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See detailInfrared colours of star-forming galaxies and a flux calibration of ISOCAM ELAIS catalogues
Vaisanen, Petri; Morel, Thierry ULg

in Exploiting the ISO Data Archive. Infrared Astronomy in the Internet Age (2003, February 01)

We present J and K-band near-infrared photometry of a sample of ISOCAM sources detected by the European Large Area ISO-Survey (ELAIS). All of the high-reliability LW2 (6.7 μm) sources and 80 per cent of ... [more ▼]

We present J and K-band near-infrared photometry of a sample of ISOCAM sources detected by the European Large Area ISO-Survey (ELAIS). All of the high-reliability LW2 (6.7 μm) sources and 80 per cent of the LW3 (15 μm) sources are identified in the near-IR survey reaching K â 17.5 mag. The near- to mid-IR flux ratios can effectively be used to separate stars from galaxies in mid-IR surveys: at 6.7 μm, 80 per cent of the identified ELAIS objects are stars while at 15 μm 80 per cent are galaxies. The stars are then used to perform an accurate new calibration of the ELAIS ISOCAM data at both 6.7 and 15 μm: we adopt values of 1.23 and 1.05 ADU/gain/s/mJy for the LW2 and LW3 filters, respectively. The ISOCAM ELAIS survey is found to mostly detect strongly star-forming late-type galaxies. We show that near to mid-IR colour-colour diagrams can be used to further classify galaxies, as well as study star-formation. In a [15/2.2] vs. [6.7/2.2] plot the Hubble type of a galaxy can be roughly estimated from its position along the diagonal ([6.7/15] = 1) and the star-forming efficiency from a galaxys departure from the diagonal (eg. [6.7/15] <1). The ELAIS galaxies yield an average mid-IR flux ratio LW2/LW3 =0.67 ± 0.27. We discuss this [6.7/15] ratio as a star formation tracer using ISO and IRAS data of a local comparison sample. The [2.2/15] ratio is also found to be a good indicator of activity level in galaxies and conclude that the drop in the [6.7/15] ratio seen in strongly star-forming galaxies is a result of both an increase of 15 μm emission and an apparent depletion of 6.7 μm emission. [less ▲]

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See detailNear- and mid-infrared colours of star-forming galaxies in European Large Area ISO Survey fields
Vaisanen, Petri; Morel, Thierry ULg; Rowan-Robinson, M. et al

in Monthly Notices of the Royal Astronomical Society (2002), 337

We present J- and K-band near-infrared (near-IR) photometry of a sample of mid-infrared (mid-IR) sources detected by the Infrared Space Observatory (ISO) as part of the European Large Area ISO Survey ... [more ▼]

We present J- and K-band near-infrared (near-IR) photometry of a sample of mid-infrared (mid-IR) sources detected by the Infrared Space Observatory (ISO) as part of the European Large Area ISO Survey (ELAIS) and study their classification and star-forming properties. We have used the Preliminary ELAIS Catalogue for the 6.7-μm (LW2) and 15-μm (LW3) fluxes. All of the high-reliability LW2 sources and 80 per cent of the LW3 sources are identified in the near-IR survey reaching K~ 17.5 mag. The near-IR/mid-IR flux ratios can effectively be used to separate stars from galaxies in mid-IR surveys. The stars detected in our survey region are used to derive a new accurate calibration for the ELAIS ISOCAM data in both the LW2 and LW3 filters. We show that near- to mid-IR colour-colour diagrams can be used to classify galaxies further, as well as to study star formation. The ELAIS ISOCAM survey is found mostly to detect strongly star-forming late-type galaxies, possibly starburst-powered galaxies, and it also picks out obscured active galactic nuclei. The ELAIS galaxies yield an average mid-IR flux ratio LW2/LW3 = 0.67 +/- 0.27. We discuss the f[SUB]ν[/SUB](6.7 μ m)/f[SUB]ν[/SUB](15 μ m) ratio as a star formation tracer using ISO and IRAS data of a local comparison sample. We find that the f[SUB]ν[/SUB](2.2 μ m)/f[SUB]ν[/SUB](15 μ m) ratio is also a good indicator of activity level in galaxies and conclude that the drop in the f[SUB]ν[/SUB](6.7 μ m)/f[SUB]ν[/SUB](15 μ m) ratio seen in strongly star-forming galaxies is a result of both an increase of 15-μm emission and an apparent depletion of 6.7-μm emission. Near-IR together with the mid-IR data make it possible to estimate the relative amount of interstellar matter in the galaxies. [less ▲]

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See detailThe Quadruple Wolf-Rayet System GP Cephei: Spectral Types, Masses, Mass-Loss Rate, and Colliding Winds
Demers, H.; Moffat, A. F. J.; Marchenko, S. V. et al

in Astrophysical Journal (2002), 577

We have reevaluated the orbital elements for each pair of the quadruple (W-R+O) + (O+O) stellar system GP Cep and propose new spectral types WN6o/WCE + O3-6, B0: I + B1: V-III. It is shown that there is ... [more ▼]

We have reevaluated the orbital elements for each pair of the quadruple (W-R+O) + (O+O) stellar system GP Cep and propose new spectral types WN6o/WCE + O3-6, B0: I + B1: V-III. It is shown that there is only one Wolf-Rayet (W-R) star in GP Cep, contrary to a previous claim. A rate of change P=1.3+/-0.2 s yr[SUP]-1[/SUP] is determined for the W-R+O pair, which leads to a new period of 6.6887 days and to a W-R mass-loss rate of (0.8-3.0)à 10[SUP]-5[/SUP] M[SUB]solar[/SUB] yr[SUP]-1[/SUP]. Masses for this pair are estimated to be M[SUB]W-R[/SUB]>~6 M[SUB]solar[/SUB] and M[SUB]O[/SUB]>~21 M[SUB]solar[/SUB]. The effects of wind-wind collision in the W-R+O pair are studied. It is shown that even after allowing for dilution by the OB components of the quadruple system, these effects are not as strong as in the binary V444 Cygni (WN5+O6, P=4.212 days). In GP Cep, the phase-dependent, relatively weak excess emission does not originate in the arms of the bow shock cone. Rather, it emerges from the extra heated portion of the W-R wind facing the hot O companion. The trailing bow shock arm is clearly seen, however, as an enhanced He I absorption component near quadrature at phase ~0.73. An anomalous blueshifted He I absorption is present at phase ~0.9, as is also seen in V444 Cyg, in the WC8+O9 I/O8 III binary γ Velorum and in the LBV-cotype binary R81 (B2.5 Iab:e). A 3.5 day orbit for the eclipsing B star pair is confirmed. [less ▲]

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See detailNear-infrared [Fe II] emission from supernova remnants and the supernova rate of starburst galaxies
Morel, Thierry ULg; Doyon, R.; St-Louis, N.

in Monthly Notices of the Royal Astronomical Society (2002), 329

In an effort better to calibrate the supernova rate of starburst galaxies as determined from near-infrared [FeII] features, we report on a [FeII] λ1.644μm line-imaging survey of a sample of 42 optically ... [more ▼]

In an effort better to calibrate the supernova rate of starburst galaxies as determined from near-infrared [FeII] features, we report on a [FeII] λ1.644μm line-imaging survey of a sample of 42 optically selected supernova remnants (SNRs) in M33. A wide range of [FeII] luminosities are observed within our sample (from less than 6 to 695L[SUB]solar[/SUB]). Our data suggest that the bright [FeII] SNRs are entering the radiative phase and that the density of the local interstellar medium (ISM) largely controls the amount of [FeII] emission. We derive the following relation between the [FeII] λ1.644μm line luminosity of radiative SNRs and the electronic density of the post-shock gas, n[SUB]e[/SUB]: L[SUB][FeII][/SUB] (L[SUB]solar[/SUB])~1.1n[SUB]e[/SUB] (cm[SUP]-3[/SUP]). We also find a correlation in our data between L[SUB][FeII][/SUB] and the metallicity of the shock-heated gas, but the physical interpretation of this result remains inconclusive, as our data also show a correlation between the metallicity and n[SUB]e[/SUB]. The dramatically higher level of [FeII] emission from SNRs in the central regions of starburst galaxies is most likely due to their dense environments, although metallicity effects might also be important. The typical [FeII]-emitting lifetime of a SNR in the central regions of starburst galaxies is found to be of the order of 10[SUP]4[/SUP]yr. On the basis of these results, we provide a new empirical relation allowing the determination of the current supernova rate of starburst galaxies from their integrated near-infrared [FeII] luminosity. [less ▲]

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See detailThe European Large Area ISO Survey - VI. Discovery of a new hyperluminous infrared galaxy
Morel, Thierry ULg; Efstathiou, A.; Serjeant, S. et al

in Monthly Notices of the Royal Astronomical Society (2001), 327

We report the discovery of the first hyperluminous infrared galaxy (HyLIG) in the course of the European Large Area ISO Survey (ELAIS). This object has been detected by ISO at 6.7, 15 and 90μm, and is ... [more ▼]

We report the discovery of the first hyperluminous infrared galaxy (HyLIG) in the course of the European Large Area ISO Survey (ELAIS). This object has been detected by ISO at 6.7, 15 and 90μm, and is found to be a broad-line, radio-quiet quasar at a redshift [formmu4]z=1.099. From a detailed multicomponent model fit of the spectral energy distribution, we derive a total IR luminosity L[SUB]IR[/SUB] [formmu5](1-1000μm)~1.0à 10[SUP]13[/SUP]h65-2L[SUB]solar[/SUB] [formmu6](q[SUB]0[/SUB]=0.5), and discuss the possible existence of a starburst contributing to the far-IR output. Observations to date present no evidence for lens magnification. This galaxy is one of the very few HyLIGs with a X-ray detection. On the basis of its soft X-ray properties, we suggest that this broad-line object may be the face-on analogue of narrow-line, Seyfert-like HyLIGs. [less ▲]

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See detailOptical spectroscopy of X-Mega targets - II. The massive double-lined O-type binary HD 93205
Morrell, N. I.; Barbá, R. H.; Niemela, V. S. et al

in Monthly Notices of the Royal Astronomical Society (2001), 326

A new high-quality set of orbital parameters for the O-type spectroscopic binary HD 93205 has been obtained combining échelle and coudé CCD observations. The radial velocity orbits derived from the Heii ... [more ▼]

A new high-quality set of orbital parameters for the O-type spectroscopic binary HD 93205 has been obtained combining échelle and coudé CCD observations. The radial velocity orbits derived from the Heii lambda4686Å (primary component) and Hei lambda4471Å (secondary component) absorption lines yield semi-amplitudes of 133+/-2 and 314+/-2kms[SUP]-1[/SUP] for each binary component, resulting in minimum masses of 31 and 13M[SUB]solar[/SUB] (q=0.42). We also confirm for the binary components the spectral classification of O3V+O8V previously assigned. Assuming for the O8V component a `normal' mass of 22-25M[SUB]solar[/SUB] we would derive for the primary O3V a mass of `only' 52-60M[SUB]solar[/SUB] and an inclination of about 55° for the orbital plane. We have also determined for the first time a period of apsidal motion for this system, namely 185+/-16yr using all available radial velocity data sets of HD 93205 (from 1975 to 1999). Phase-locked variations of the X-ray emission of HD 93205 consisting of a rise of the observed X-ray flux near periastron passage are also discussed. [less ▲]

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See detailMid-FIR Properties of ELAIS Sources
Marquez, I.; Masegosa, J.; Morel, Thierry ULg et al

in The Promise of the Herschel Space Observatory (2001, July 01)

We present the properties of all the galaxies detected by ISO at 7, 15 and 90 microns in ELAIS northern fields. The spectral energy distribution (SED) of those 20 galaxies with IRAS detections can ... [more ▼]

We present the properties of all the galaxies detected by ISO at 7, 15 and 90 microns in ELAIS northern fields. The spectral energy distribution (SED) of those 20 galaxies with IRAS detections can generally be well fitted by a predominant cirrus component plus a modest starburst contribution. Follow-up spectroscopy has shown that all the objects are emission-line galaxies but without a very intense star formation event. Most of the galaxies analyzed by means of optical R band photometry result to host an important exponential disk component, in good agreement with the SED IR modelling. We note that galaxies with morphological signs of perturbations seem to show slightly higher f[SUB]15[/SUB]/f[SUB]6.7[/SUB] ratios, indicating that star formation could be more important in them. One of the objects is a broad-line, radio-quiet quasar at z=1.099; its spectral energy distribution indicates that it is a hyperluminous infrared galaxy (HLIG), the first HLIG detected in the ELAIS areas. [less ▲]

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See detailSpectroscopic Properties of New IR Galaxies Detected in the European Large Area ISO Survey
Cabrera-Guerra, F.; Perez-Fournon, I.; Gonzalez-Solares, E. A. et al

in The Promise of the Herschel Space Observatory (2001, July 01)

We present preliminary results of multi-object spectroscopy of new mid-, and far-infrared selected galaxies detected in the European Large Area ISO Survey (ELAIS). The data have been obtained with the ... [more ▼]

We present preliminary results of multi-object spectroscopy of new mid-, and far-infrared selected galaxies detected in the European Large Area ISO Survey (ELAIS). The data have been obtained with the fibre spectrographs WYFFOS at the William Herschel Telescope (Observatorio del Roque de los Muchachos, ORM, Canary Islands) and Hydra at the WIYN Telescope (Kitt Peak Observatory, Arizona). The sample includes ISO sources detected at 7, 15 and 90 microns and radio sources from our deep VLA survey in the ELAIS areas. [less ▲]

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See detailThe European Large Area ISO Survey - IV. The preliminary 90-microns luminosity function
Serjeant, S.; Efstathiou, A.; Oliver, S. et al

in Monthly Notices of the Royal Astronomical Society (2001), 322

We present the luminosity function of 90-μm-selected galaxies from the European Large Area ISO Survey (ELAIS), extending to z=0.3. Their luminosities are in the range 10[SUP]9[/SUP]< h 65 -2L/L[SUB]solar ... [more ▼]

We present the luminosity function of 90-μm-selected galaxies from the European Large Area ISO Survey (ELAIS), extending to z=0.3. Their luminosities are in the range 10[SUP]9[/SUP]< h 65 -2L/L[SUB]solar[/SUB]<10[SUP]12[/SUP], i.e. non-ultraluminous. From our sample of 37 reliably detected galaxies in the ELAIS S1 region from the Efstathiou et al. S[SUB]90[/SUB]>=100mJy data base, we have found optical, 15-μm or 1.4-GHz identifications for 24 (65 per cent). We have obtained 2dF and UK Schmidt FLAIR spectroscopy of 89 per cent of identifications to rigid multivariate flux limits. We construct a luminosity function assuming that (i) our spectroscopic subset is an unbiased sparse sample, and (ii) there are no galaxies that would not be represented in our spectroscopic sample at any redshift. We argue that we can be confident of both assumptions. We find that the luminosity function is well described by the local 100-μm luminosity function of Rowan-Robinson, Helou & Walker. Assuming this local normalization, we derive luminosity evolution of (1+z)[SUP]2.45+/-0.85[/SUP] (95 per cent confidence). We argue that star formation dominates the bolometric luminosities of these galaxies, and we derive comoving star formation rates in broad agreement with the Flores et al. and Rowan-Robinson et al. mid-infrared-based estimates. [less ▲]

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