Bulge microlensing optical depth from EROS 2
 observations $^{\bullet}$

Afonso, C.; Albert, J.; Alard, C.; Andersen, J.; Ansari, R.; Aubourg, É.; Bareyre, P.; Bauer, F. F.; Beaulieu, J. P.; Blanc, G.; Bouquet, A.; Char, S.; Charlot, X.; Couchot, F.; Coutures, C.; Derue, F.; Ferlet, R.; Fouqué, P.; Glicenstein, J. F.; Goldman, B.; Gould, Andrew; Graff, D.; Gros, M.; Haïssinski, J.; Hamadache, C.; Hamilton, J. C.; Hardin, D.; Kat, J. de; Kim, A.; Lasserre, T.; Guillou, L. Le; Lesquoy, É.; Loup, C.; Magneville, C.; Mansoux, B.; Marquette, J. B.; Maurice, É.; Maury, A.; Milsztajn, A.; Moniez, M.; Palanque-Delabrouille, N.; Perdereau, O.; Prévôt, L.; Regnault, Nicolas; Rich, J.; Spiro, M.; Tisserand, Patrick; Vidal‐Madjar, A.; Vigroux, L.; Zylberajch, S.

doi:10.1051/0004-6361:20030307

Cited by 75 publications

(86 citation statements)

References 30 publications

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“…Besides the Magellanic results presented here, EROS-2 has also published measurements of the optical depth toward the Galactic Bulge (Afonso et al 2003b;Hamadache et al 2006). The measured optical depth is in agreement with that measured by MACHO (Popowski et al 2005), and OGLE-2 (Sumi et al 2006) and with the predictions of Galactic models (Evans & Belokurov 2002;Bissantz & Gerhard 2002;Han & Gould 2003;Wood & Mao 2005).…”

Section: Introductionmentioning

confidence: 82%

Limits on the Macho content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds

Tisserand

Guillou

Afonso

et al. 2007

A&A

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Aims. The EROS-2 project was designed to test the hypothesis that massive compact halo objects (the so-called "machos") could be a major component of the dark matter halo of the Milky Way galaxy. To this end, EROS-2 monitored over 6.7 years 33 × 10 6 stars in the Magellanic clouds for microlensing events caused by such objects. Methods. In this work, we use only a subsample of 7 × 10 6 bright stars spread over 84 deg 2 of the LMC and 9 deg 2 of the SMC. The strategy of using only bright stars helps to discriminate against background events due to variable stars and allows a simple determination of the effects of source confusion (blending). The use of a large solid angle makes the survey relatively insensitive to effects that could make the optical depth strongly direction dependent. Results. Using this sample of bright stars, only one candidate event was found, whereas ∼39 events would have been expected if the Halo were entirely populated by objects of mass M ∼ 0.4 M . Combined with the results of EROS-1, this implies that the optical depth toward the Large Magellanic Cloud (LMC) due to such lenses is τ < 0.36 × 10 −7 (95% CL), corresponding to a fraction of the halo mass of less than 8%. This optical depth is considerably less than that measured by the MACHO collaboration in the central region of the LMC. More generally, machos in the mass range 0.6 × 10 −7 M < M < 15 M are ruled out as the primary occupants of the Milky Way Halo.

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Section: Introductionmentioning

confidence: 82%

Limits on the Macho content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds

Tisserand

Guillou

Afonso

et al. 2007

A&A

Self Cite

915

908

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“…The Expérience de Recherche d'Objets Sombres (EROS-2) project employed extensive photometry obtained with the 1-m MARLY telescope at La Silla Observatory, Chile, to search for the baryonic dark matter of the Galactic halo by means of the gravitational microlensing (Afonso et al 2003;Lasserre et al 2000;Palanque-Delabrouille et al 1998;Tisserand et al 2007). The observations were performed between July 1996 and February 2003 through a dichroic plate-splitting light into two wide field cameras covering 0.7×1.4 • in right ascension and declination each, yielding two broad passbands.…”

Section: Eros-2 Surveymentioning

confidence: 99%

Oxygen- and carbon-rich variable red giant populations in the Magellanic Clouds from EROS, OGLE, MACHO, and 2MASS photometry

Wiśniewski

Marquette

Beaulieu

et al. 2011

A&A

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Context. The carbon-to-oxygen (C/O) ratio of asymptotic giant branch (AGB) stars constitutes an important index of evolutionary and environment/metallicity factor. Aims. We develop a method for mass C/O classification of AGBs in photometric surveys without using periods. Methods. For this purpose we rely on the slopes in the tracks of individual stars in the colour-magnitude diagram. Results. We demonstrate that our method enables the separation of C-rich and O-rich AGB stars with little confusion. For the Magellanic Clouds we demonstrate that this method works for several photometric surveys and filter combinations. As we rely on no period identification, our results are relatively insensitive to the phase coverage, aliasing, and time-sampling problems that plague period analyses. For a subsample of our stars, we verify our C/O classification against published C/O catalogues. With our method we are able to produce C/O maps of the entire Magellanic Clouds. Conclusions. Our purely photometric method for classification of C-and O-rich AGBs constitutes a method of choice for large, near-infrared photometric surveys. Because our method depends on the slope of colour-magnitude variation but not on magnitude zero point, it remains applicable to objects with unknown distances.

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“…BG give an optical depth map for clump giant stars in their model with maximum M/L. For the clump giant stars the most secure optical depths can be measured; the published values to date are, in units of 10 −6 , τ −6 = 2.17 +0.47 Popowski et al 2005), and τ −6 = 0.96 ± 0.3 at (l, b) = (2.5 • , −4 • ) (EROS collaboration, Afonso et al 2003). The BG model predicts τ −6 = 2.4 and τ −6 = 1.2 at these positions, slightly higher but within the errors.…”

Section: Mass Of the Bulge And Diskmentioning

confidence: 99%

Mass Distribution and Bulge Formation in the Milky Way Galaxy

Gerhard¹

2006

EAS Publications Series

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Abstract. In its first part, this paper summarizes recent work on the mass and shape of the Galactic dark halo. The second part presents a review of the large-scale structure of the Milky Way, and of the evidence that the inner Galaxy is dominated by baryonic matter. This is briefly compared with the predictions of ΛCDM and MOND. Finally, a summary is given of bulge formation from clumpy, gas-rich disks, a process which may give rise to old, disk-like, α-rich bulges similar to the Galactic bulge.

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Bulge microlensing optical depth from EROS 2 observations $^{\bullet}$

Cited by 75 publications

References 30 publications

Limits on the Macho content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds

Limits on the Macho content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds

Oxygen- and carbon-rich variable red giant populations in the Magellanic Clouds from EROS, OGLE, MACHO, and 2MASS photometry

Mass Distribution and Bulge Formation in the Milky Way Galaxy

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