Testing LMC Microlensing Scenarios: The Discrimination Power of the SuperMACHO Microlensing Survey

By Armin Rest, C. Stubbs, A. Becker, G. Miknaitis, A. Miceli, R. Covarrubias, S. Hawley, R. Smith, N. Suntzeff, Knut A. G. Olsen and 13 more. 2005

180 citations recorded by the source corpus.

Characterizing the nature and spatial distribution of the lensing objects that produce the previously measured microlensing optical depth toward the Large Magellanic Cloud (LMC) remains an open problem. We present an appraisal of the ability of the SuperMACHO Project, a next-generation microlensing survey directed toward the LMC, to discriminate between various proposed lensing populations. We consider two scenarios: lensing by a uniform foreground screen of objects and self-lensing by LMC stars. The optical depth for "screen lensing" is essentially constant across the face of the LMC, whereas the optical depth for self-lensing shows a strong spatial dependence. We have carried out extensive simulations, based on data obtained during the first year of the project, to assess the SuperMACHO survey's ability to discriminate between these two scenarios. In our simulations we predict the expected number of observed microlensing events for various LMC models for each of our fields by adding artificial stars to the images and estimating the spatial and temporal efficiency of detecting microlensing events using Monte Carlo methods. We find that the event rate itself shows significant sensitivity to the choice of the LMC luminosity function, limiting the conclusions that can be drawn from the absolute rate. If instead we determine the differential event rate across the LMC, we will decrease the impact of these systematic biases and render our conclusions more robust. With this approach the SuperMACHO Project should be able to distinguish between the two categories of lens populations. This will provide important constraints on the nature of the lensing objects and their contributions to the Galactic dark matter halo.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/9c2ed9025f2bf2abbc2d8002a5f7f72e28f041b1

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Citations in the corpus

Type Ia Supernovae Are Good Standard Candles in the Near Infrared: Evidence from PAIRITEL (2007, methodology): “Photometry Mosaicked images were fed to the photometry pipeline we have used in the ESSENCE and SuperMACHO projects (Rest et al. 2005; Garg et al. 2007; Miknaitis et al. 2007).”
FROM SHOCK BREAKOUT TO PEAK AND BEYOND: EXTENSIVE PANCHROMATIC OBSERVATIONS OF THE TYPE Ib SUPERNOVA 2008D ASSOCIATED WITH SWIFT X-RAY TRANSIENT 080109 (2008, methodology): “For the NIR photometry, we used the image-analysis pipeline of the ESSENCE and SuperMACHO projects (Rest et al. 2005; Garg et al. 2007; Miknaitis et al. 2007).”
GALAXY CLUSTERS DISCOVERED VIA THE SUNYAEV–ZEL’DOVICH EFFECT IN THE FIRST 720 SQUARE DEGREES OF THE SOUTH POLE TELESCOPE SURVEY (2012, methodology): “Optical/NIR Imaging Data Reduction and Redshift Determination All optical images are processed using the PHOTPIPE analysis pipeline (Rest et al. 2005; Miknaitis et al. 2007), as was done in previous SPT optical follow up analyses (High et al. 2010; Williamson et al. 2011; Story et al. 2011).”
CfA4: LIGHT CURVES FOR 94 TYPE Ia SUPERNOVAE (2012, methodology): “The reduction and subtraction stages were carried out by a version of the ESSENCE and SuperMACHO pipeline (Miknaitis et al. 2007; Rest et al. 2005; Garg et al. 2007).”
Pan-STARRS1 DISCOVERY OF TWO ULTRALUMINOUS SUPERNOVAE AT z ≈ 0.9 (2011, background): “Difference images are produced from the stacked images by the photpipe pipeline (Rest et al. 2005) and potential transients are visually inspected by humans for possible promotion to the status of transient alerts.”
GALAXY CLUSTERS DISCOVERED VIA THE SUNYAEV–ZEL'DOVICH EFFECT IN THE 2500-SQUARE-DEGREE SPT-SZ SURVEY (2014, methodology): “With the exception of images from Magellan/Megacam (McLeod et al. 2006), all optical images were reduced with the PHOTPIPE pipeline (Rest et al. 2005; Garg et al. 2007; Miknaitis et al. 2007).”
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. II. UV, Optical, and Near-infrared Light Curves and Comparison to Kilonova Models (2017, methodology): “We processed all of the DECam images using the photpipe pipeline (e.g., Rest et al. 2005, 2014) in order to perform single-epoch image processing and image subtraction using the hotpants software package (Becker 2015).”
CfA3: 185 TYPE Ia SUPERNOVA LIGHT CURVES FROM THE CfA (2009, methodology): “The reduction and subtraction stages are carried out by a version of the ESSENCE and SuperMACHO pipeline (Miknaitis et al. 2007; Rest et al. 2005; Garg et al. 2007), modified for use on the CfA3 data.”
THE ULTRAVIOLET-BRIGHT, SLOWLY DECLINING TRANSIENT PS1-11af AS A PARTIAL TIDAL DISRUPTION EVENT (2013, methodology): “We construct deep template observations from the preoutburst images and subtract them from the PS1 observations using photpipe (Rest et al. 2005).”
RAPIDLY EVOLVING AND LUMINOUS TRANSIENTS FROM PAN-STARRS1 (2014, methodology): “The nightly PS1-MDS stacks are then transferred to the Harvard FAS Research Computing cluster where difference images are produced and potential transients identified by the photpipe pipeline (Rest et al. 2005, 2013).”
HYDROGEN-POOR SUPERLUMINOUS SUPERNOVAE AND LONG-DURATION GAMMA-RAY BURSTS HAVE SIMILAR HOST GALAXIES (2013, methodology): “…nightly MDS stacks are transferred to the Harvard FAS Research Computing cluster, where they are processed through a frame subtraction analysis using the photpipe pipeline developed for the SuperMACHO and ESSENCE surveys (Rest et al. 2005; Garg et al. 2007; Miknaitis et al. 2007; Rest et al. 2013).”
The Complete Light-curve Sample of Spectroscopically Confirmed SNe Ia from Pan-STARRS1 and Cosmological Constraints from the Combined Pantheon Sample (2017, methodology): “H08 explains that the largest benefits to the scene-modeling approach over the conventional template construction (e.g., as in Photpipe) are when the depth or PSF size of the template images is less than or equal to the depth or seeing of the SN images.”
TOWARD CHARACTERIZATION OF THE TYPE IIP SUPERNOVA PROGENITOR POPULATION: A STATISTICAL SAMPLE OF LIGHT CURVES FROM Pan-STARRS1 (2014, methodology): “…the Harvard Faculty of Arts and Sciences “Odyssey” Research Computing cluster, where they are processed through a frame subtraction analysis using the photpipe image differencing pipeline developed for the SuperMACHO and ESSENCE surveys (Rest et al. 2005; Miknaitis et al. 2007; Rest et al. 2013).”
COSMOLOGICAL CONSTRAINTS FROM MEASUREMENTS OF TYPE Ia SUPERNOVAE DISCOVERED DURING THE FIRST 1.5 yr OF THE Pan-STARRS1 SURVEY (2013, methodology): “The nightly MDF stacked images are processed through a frame-subtraction analysis using the photpipe pipeline that members of our team developed for the SuperMACHO and ESSENCE surveys (Rest et al. 2005; Garg et al. 2007; Miknaitis et al. 2007).”
THE BLANCO COSMOLOGY SURVEY: DATA ACQUISITION, PROCESSING, CALIBRATION, QUALITY DIAGNOSTICS, AND DATA RELEASE (2012, methodology): “All four seasons of BCS data have also been processed independently using NOAO pipeline as part of the current automated processing program, and with the PHOTPIPE analysis pipeline (Rest et al. 2005).”