Galactic Bulge Microlensing Optical Depth from EROS-2

Abstract

We present a new EROS-2 measurement of the microlensing optical depth toward the Galactic Bulge. Light curves of $5.6\times 10^6$ clump-giant stars distributed over $66{°}^2$ of the Bulge were monitored during seven Bulge seasons. 120 events were found with apparent amplifications greater than 1.6 and Einstein radius crossing times in the range $5 {\rm d}<t_\e <400 {\rm d}$. This is the largest existing sample of clump-giant events and the first to include northern Galactic fields. In the Galactic latitude range $1.4\degr<|b|<7.0\degr$, we find $\tau /10^{-6}=(1.62\pm 0.23)\exp [-a(|b|-3\mathrm{deg})]$ with $a=(0.43\pm 0.16){°}^{-1}$. These results are in good agreement with our previous measurement, with recent measurements of the MACHO and OGLE-II groups, and with predictions of Bulge models.

accepted A&A, minor revisions

References in corpus (27)

• The MACHO Project: Microlensing Results from 5.7 Years of LMC Observations
• LCDM-based models for the Milky Way and M31 I: Dynamical Models
• First GLIMPSE Results on the Stellar Structure of the Galaxy
• The photometric structure of the inner Galaxy
• COBE's Galactic Bar and Disk
• Spiral arms, bar shape and bulge microlensing in the Milky Way
• The Luminosity Function and Mass Function in the Galactic Bulge
• Microlensing optical depth towards the Galactic bulge from MOA observations during 2000 with Difference Image Analysis
• Stellar Contribution to the Galactic Bulge Microlensing Optical Depth
• Color-Magnitude Diagram Distribution of the Bulge Red Clump Stars - Evidence for the Galactic Bar
• The MACHO Project: 45 Candidate Microlensing Events from the First Year Galactic Bulge Data
• The MACHO project: Microlensing Optical Depth towards the Galactic Bulge from Difference Image Analysis
• Microlensing Optical Depth towards the Galactic Bulge Using Clump Giants from the MACHO Survey
• Statistics Of Microlensing Optical Depth
• POINT-AGAPE Pixel Lensing Survey of M31 : Evidence for a MACHO contribution to Galactic Halos
• Microlensing optical depth toward the Galactic Bulge using bright sources from OGLE-II
• Bulge Microlensing Optical Depth from EROS 2 observations
• Large-Scale Model of the Milky Way: Stellar Kinematics and Microlensing Event Timescale Distribution in the Galactic Bulge
• The Wendelstein Calar Alto Pixellensing Project(WeCAPP): First MACHO Candidates
• Observation of Microlensing towards the Galactic Spiral Arms. EROS II 3 year survey
• Optical Depths and Timescale Distributions in Galactic Microlensing
• MACHOs in M31? Absence of evidence but not evidence of absence
• Is Galactic Structure Compatible with Microlensing Data?
• Evidence of Halo Microlensing in M31
• Microlensing Maps for the Milky Way Galaxy
• First microlensing candidate towards M31 from the Nainital Microlensing Survey
• K Band Microlensing of the Inner Galaxy

Cited by in corpus (73)

• New cosmological constraints on primordial black holes
• Primordial Black Holes as Dark Matter
• Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report
• Limits on the Macho Content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds
• Primordial Black Holes as Dark Matter: Recent Developments
• Unbound or Distant Planetary Mass Population Detected by Gravitational Microlensing
• Improved Estimates of the Milky Way's Stellar Mass and Star Formation Rate from Hierarchical Bayesian Meta-Analysis
• Effect of Primordial Black Holes on the Cosmic Microwave Background and Cosmological Parameter Estimates
• Primordial Black Holes as Generators of Cosmic Structures
• The Milky Way's Stellar Disk
• Dark Matter distribution in the Milky Way: microlensing and dynamical constraints
• Primordial Black Holes as Dark Matter Candidates
• The fraction of dark matter within galaxies from the IllustrisTNG simulations
• Korea Microlensing Telescope Network Microlensing Events from 2015: Event-Finding Algorithm, Vetting, and Photometry
• Unifying boxy bulge and planar long bar in the Milky Way
• ExELS: an exoplanet legacy science proposal for the ESA Euclid mission I. Cold exoplanets
• Bondi accretion in the early universe
• Astrophysical Applications of Gravitational Microlensing
• Microlensing optical depth and event rate toward the Galactic bulge from 8 yr of OGLE-IV observations
• The Microlensing Event Rate and Optical Depth Toward the Galactic Bulge from MOA-II
• OGLE-III Microlensing Events and the Structure of the Galactic Bulge
• Primordial Black Holes
• Nomads of the Galaxy
• MOA-II Galactic Microlensing Constraints: The Inner Milky Way has a Low Dark Matter Fraction and a Near Maximal Disk
• The OGLE View of Microlensing towards the Magellanic Clouds. I. A Trickle of Events in the OGLE-II LMC data
• Optimal Survey Strategies and Predicted Planet Yields for the Korean Microlensing Telescope Network
• New Magellanic Cloud R Coronae Borealis and DY Per type stars from the EROS-2 database: the connection between RCBs, DYPers and ordinary carbon stars
• Microlensing constraints on the Galactic Bulge Initial Mass Function
• Microlensing as a probe of the Galactic structure; 20 years of microlensing optical depth studies
• Blending in Gravitational Microlensing Experiments: Source Confusion And Related Systematics
• Bar slowdown and the distribution of dark matter in barred galaxies
• High precision microlensing maps of the Galactic bulge
• Possible Solution of the long-standing discrepancy in the Microlensing Optical Depth Toward the Galactic Bulge by correcting the stellar number count
• R Coronae Borealis stars in the Galactic Bulge discovered by EROS-2
• Microlensing towards the LMC: self lensing for OGLE-II and OGLE-III
• The EROS2 search for microlensing events towards the spiral arms: the complete seven season results
• Besançon Galactic model analysis of MOA-II microlensing: evidence for a mass deficit in the inner bulge
• Observational constraints on light cosmic strings from photometry and pulsar timing
• Understanding EROS2 observations toward the spiral arms within a classical Galactic model framework
• Pixel lensing: Microlensing towards M31
• Full orbital solution for the binary system in the northern Galactic disc microlensing event Gaia16aye
• LMC self lensing for OGLE-II microlensing observations
• Discovery of a Very Bright, Nearby Gravitational Microlensing Event
• Press-Schechter primordial black hole mass functions and their observational constraints
• Detection of Extrasolar Planets by Gravitational Microlensing
• Constraining the dark matter content of NGC 1291 using hydrodynamic gas response simulations
• Planetary microlensing signals from the orbital motion of the source star around the common barycentre
• Evidence for non-axisymmetry in M31 from wide-field kinematics of stars and gas
• Near-Field Microlensing from Wide-Field Surveys
• Statistical Searches for Microlensing Events in Large, Non-Uniformly Sampled Time-Domain Surveys: A Test Using Palomar Transient Factory Data
• New R Coronae Borealis stars discovered in OGLE-III Galactic Bulge fields from their mid- and near- infrared properties
• Probing isolated compact remnants with microlensing
• The Galactic Bulge: A Review
• Gravitational microlensing as a test of a finite-width disk model of the Galaxy
• FRBs Lensed by Point Masses II. The multi-peaked FRBs from the point view of microlensing
• Detection of M31 Binaries via High-Cadence Pixel-Lensing Surveys
• Studying wave optics in the light curve of exoplanet microlensing
• Searching for Galactic hidden gas through interstellar scintillation: Results from a test with the NTT-SOFI detector
• The Prime Focus Infrared Microlensing Experiment (PRIME): First Results
• Constraining the vertical structure of the Milky Way rotation by microlensing in a finite-width global disk model
• Exoplanetary Microlensing
• Microlensing Optical Depth Revisited with Recent Star Counts
• Gravitational Microlensing Event Statistics for the Zwicky Transient Facility
• The Futile Search for Galactic Disk Dark Matter
• Galactic globular clusters contribution to microlensing events?
• Using microlensed quasars to probe the structure of the Milky Way
• Microlensing optical depth as a function of source apparent magnitude
• VVV survey microlensing: candidate events with source in the far disk
• Microlensing pulsars
• Discovery of a peculiar Cepheid-like star towards the northern edge of the Small Magellanic Cloud
• EROS light curve data base
• Limits on compact halo objects as dark matter from gravitational microlensing
• Microlensing and Variability in the Bulge of M31