Mass measurements of isolated objects from space-based microlensing

We report on the mass and distance measurements of two single-lens events from the 2015 Spitzer microlensing campaign. With both finite-source effect and microlens parallax measurements, we find that the lens of OGLE-2015-BLG-1268 is very likely a brown dwarf (BD). Assuming that the source star lies behind the same amount of dust as the Bulge red clump, we find the lens is a 45 ± 7 M_jup }BD at 5.9 ± 1.0 kpc. The lens of of the second event, OGLE-2015-BLG-0763, is a 0.50 ± 0.04 M_sun star at 6.9 ± 1.0 kpc. We show that the probability to definitively measure the mass of isolated microlenses is dramatically increased once simultaneous ground- and space-based observations are conducted.

Citation

Zhu , W , Calchi Novati , S , Gould , A , Udalski , A , Han , C , Shvartzvald , Y , Ranc , C , Jørgensen , U G , Poleski , R , Bozza , V , Beichman , C , Bryden , G , Carey , S , Gaudi , B S , Henderson , C B , Pogge , R W , Porritt , I , Wibking , B , Yee , J C , Pawlak , M , Szymański , M K , Skowron , J , Mróz , P , Kozłowski , S , Wyrzykowski , Ł , Pietrukowicz , P , Pietrzyński , G , Soszyński , I , Ulaczyk , K , Choi , J-Y , Park , H , Jung , Y K , Shin , I-G , Albrow , M D , Park , B-G , Kim , S-L , Lee , C-U , Cha , S-M , Kim , D-J , Lee , Y , Friedmann , M , Kaspi , S , Maoz , D , Hundertmark , M , Street , R A , Tsapras , Y , Bramich , D M , Cassan , A , Dominik , M , Bachelet , E , Dong , S , Figuera Jaimes , R , Horne , K , Mao , S , Menzies , J , Schmidt , R , Snodgrass , C , Steele , I A , Wambsganss , J , Skottfelt , J , Andersen , M I , Burgdorf , M J , Ciceri , S , D'Ago , G , Evans , D F , Gu , S-H , Hinse , T C , Kerins , E , Korhonen , H , Kuffmeier , M , Mancini , L , Peixinho , N , Popovas , A , Rabus , M , Rahvar , S , Tronsgaard , R , Scarpetta , G , Southworth , J , Surdej , J , von Essen , C , Wang , Y-B & Wertz , O 2016 , ' Mass measurements of isolated objects from space-based microlensing ' , Astrophysical Journal , vol. 825 , no. 1 , 60 . https://doi.org/10.3847/0004-637X/825/1/60

Publication

Astrophysical Journal

Status

Peer reviewed

DOI

https://doi.org/10.3847/0004-637X/825/1/60

ISSN

0004-637X

Type

Journal article

Rights

© 2016, American Astronomical Society. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at iopscience.iop.org / https://dx.doi.org/10.3847/0004-637X/825/1/60