References of "Vaisanen, P"
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See detailOGLE-2008-BLG-510: first automated real-time detection of a weak microlensing anomaly - brown dwarf or stellar binary?
Bozza, V.; Dominik, M.; Rattenbury, N. J. et al

in Monthly Notices of the Royal Astronomical Society (2012), 424

The microlensing event OGLE-2008-BLG-510 is characterized by an evident asymmetric shape of the peak, promptly detected by the Automated Robotic Terrestrial Exoplanet Microlensing Search (ARTEMiS) system ... [more ▼]

The microlensing event OGLE-2008-BLG-510 is characterized by an evident asymmetric shape of the peak, promptly detected by the Automated Robotic Terrestrial Exoplanet Microlensing Search (ARTEMiS) system in real time. The skewness of the light curve appears to be compatible both with binary-lens and binary-source models, including the possibility that the lens system consists of an M dwarf orbited by a brown dwarf. The detection of this microlensing anomaly and our analysis demonstrate that: (1) automated real-time detection of weak microlensing anomalies with immediate feedback is feasible, efficient and sensitive, (2) rather common weak features intrinsically come with ambiguities that are not easily resolved from photometric light curves, (3) a modelling approach that finds all features of parameter space rather than just the 'favourite model' is required and (4) the data quality is most crucial, where systematics can be confused with real features, in particular small higher order effects such as orbital motion signatures. It moreover becomes apparent that events with weak signatures are a silver mine for statistical studies, although not easy to exploit. Clues about the apparent paucity of both brown-dwarf companions and binary-source microlensing events might hide here. Based in part on data collected by MiNDSTEp with the Danish 1.54m telescope at the ESO La Silla Observatory. [less ▲]

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See detailXMM-LSS survey: AGN classifications (Garcet+, 2007)
Garcet, O.; Gandhi, P.; Gosset, Eric ULg et al

Textual, factual or bibliographical database (2007)

We have used the most up-to-date X-ray catalog (Pierre et al., 2007, Cat. J/MNRAS/382/279) to define a sample of 612 X-ray selected point-like sources which have both a log-likelihood of detection >20 ... [more ▼]

We have used the most up-to-date X-ray catalog (Pierre et al., 2007, Cat. J/MNRAS/382/279) to define a sample of 612 X-ray selected point-like sources which have both a log-likelihood of detection >20 (this roughly corresponds to >3{sigma}) in the [2-10]keV band (see Pacaud et al., 2006MNRAS.372..578P, for full details), and a total number of counts >80 in the [0.5-10]keV band. (1 data file). [less ▲]

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See detailThe XMM large scale structure survey: optical vs. X-ray classifications of active galactic nuclei and the unified scheme
Garcet, Olivier ULg; Gandhi, P.; Gosset, Eric ULg et al

in Astronomy and Astrophysics (2007), 474

Aims.Our goal is to characterize AGN populations by comparing their X-ray and optical classifications within the framework of the standard orientation-based unified scheme. Methods: We present a sample of ... [more ▼]

Aims.Our goal is to characterize AGN populations by comparing their X-ray and optical classifications within the framework of the standard orientation-based unified scheme. Methods: We present a sample of 99 spectroscopically identified (R <= 22 mag) X-ray selected point sources in the XMM-LSS survey which are significantly detected (>=3sigma) in the [ 2-10] keV band with fluxes between 8 × 10[SUP]-15[/SUP] and 8 × 10[SUP]-14[/SUP] erg s[SUP]-1[/SUP] cm[SUP]-2[/SUP], and which have more than 80 counts. We have compared their X-ray and optical classifications. To this end, we performed an X-ray spectral analysis for all of these 99 X-ray sources in order to assess whether they are intrinsically absorbed or not. The X-ray classification is based on the measured intrinsic column density. The optical classification is based on the measured FWHM of the permitted emission lines, the absence of broad lines being due to obscuration within the framework of the standard AGN unified scheme. Results: Introducing the fourfold point correlation coefficient r, we find a mild correlation between the X-ray and the optical classifications (r = 0.28), as up to 32 X-ray sources out of 99 have differing X-ray and optical classifications: on one hand, 10% of the type 1 sources (7/32) present broad emission lines in their optical spectra and strong absorption (N{H}[SUP]int[/SUP] >= 10[SUP]22[/SUP] cm[SUP]-2[/SUP]) in the X-rays. These objects are highly luminous AGN lying at high redshift and thus dilution effects by the host galaxy light are totally ruled out, their discrepant nature being an intrinsic property instead. Their X-ray luminosities and redshifts distributions are consistent with those of the unabsorbed X-ray sources with broad emission lines (L{2-10} 4 × 10[SUP]44[/SUP] erg s[SUP]-1[/SUP]; z 1.9). On the other hand, 25/32 are moderate luminosity (L{2-10} <= 5 × 10[SUP]43[/SUP] erg s[SUP]-1[/SUP]) AGN, which are both unabsorbed in the X-rays and only present narrow emission lines in their optical spectra. Based on their line ratios in the optical, the majority of them have an optical spectrum which is more representative of the host galaxy rather than of a reddened AGN. We finally infer that dilution of the AGN by the host galaxy seems to account for their nature. 5/25 have been defined as Seyfert 2 based on their optical spectra. In conclusion, most of these 32 discrepant cases can be accounted for by the standard AGN unified scheme, as its predictions are not met for only 12% of the 99 X-ray sources. Table 4 and Figs. [see full text]-[see full text] are only available in electronic form at http://www.aanda.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 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 detailThe European Large Area ISO Survey - I. Goals, definition and observations
Oliver, Seb; Rowan-Robinson, Michael; Alexander, D. M. et al

in Monthly Notices of the Royal Astronomical Society (2000), 316

We describe the European Large Area ISO Survey (ELAIS). ELAIS was the largest single Open Time project conducted by ISO, mapping an area of 12deg[SUP]2[/SUP] at 15μm with ISOCAM and at 90μm with ISOPHOT ... [more ▼]

We describe the European Large Area ISO Survey (ELAIS). ELAIS was the largest single Open Time project conducted by ISO, mapping an area of 12deg[SUP]2[/SUP] at 15μm with ISOCAM and at 90μm with ISOPHOT. Secondary surveys in other ISO bands were undertaken by the ELAIS team within the fields of the primary survey, with 6deg[SUP]2[/SUP] being covered at 6.7μm and 1deg[SUP]2[/SUP] at 175μm. This paper discusses the goals of the project and the techniques employed in its construction, as well as presenting details of the observations carried out, the data from which are now in the public domain. We outline the ELAIS `preliminary analysis' which led to the detection of over 1000 sources from the 15 and 90-μm surveys (the majority selected at 15μm with a flux limit of ~3mJy), to be fed into a ground-based follow-up campaign, as well as a programme of photometric observations of detected sources using both ISOCAM and ISOPHOT. We detail how the ELAIS survey complements other ISO surveys in terms of depth and areal coverage, and show that the extensive multi-wavelength coverage of the ELAIS fields resulting from our concerted and on-going follow-up programme has made these regions amongst the best studied areas of their size in the entire sky, and, therefore, natural targets for future surveys. This paper accompanies the release of extremely reliable subsets of the `preliminary analysis' products. Subsequent papers in this series will give further details of our data reduction techniques, reliability and completeness estimates and present the 15- and 90-μm number counts from the `preliminary analysis', while a further series of papers will discuss in detail the results from the ELAIS `final analysis', as well as from the follow-up programme. [less ▲]

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