2020AJ....159..134H

Query : 2020AJ....159..134H

2020AJ....159..134H - Astron. J., 159, 134-134 (2020/April-0)

Candidate brown-dwarf microlensing events with very short timescales and small angular Einstein radii.

HAN C., LEE C.-U., UDALSKI A., GOULD A., BOND I.A., BOZZA V., ALBROW M.D., CHUNG S.-J., HWANG K.-H., JUNG Y.K., RYU Y.-H., SHIN I.-G., SHVARTZVALD Y., YEE J.C., ZANG W., CHA S.-M., KIM D.-J., KIM H.-W., KIM S.-L., LEE D.-J., LEE Y., PARK B.-G., POGGE R.W., JEE M.J., KIM D. (The KMTNet Collaboration), MROZ P., SZYMANSKI M.K., SKOWRON J., POLESKI R., SOSZYNSKI I., PIETRUKOWICZ P., KOZLOWSKI S., ULACZYK K., RYBICKI K.A., IWANEK P., WRONA M. (The OGLE Collaboration), ABE F., BARRY R., BENNETT D.P., BHATTACHARYA A., DONACHIE M., FUJII H., FUKUI A., ITOW Y., HIRAO Y., KAMEI Y., KONDO I., KOSHIMOTO N., LI M.C.A., MATSUBARA Y., MURAKI Y., MIYAZAKI S., NAGAKANE M., RANC C., RATTENBURY N.J., SATOH Y., SHOJI H., SUEMATSU H., SULLIVAN D.J., SUMI T., SUZUKI D., TRISTRAM P.J., YAMAKAWA T., YAMAWAKI T., YONEHARA A. (The MOA Collaboration)

Abstract (from CDS):

Short-timescale microlensing events are likely to be produced by substellar brown dwarfs (BDs), but it is difficult to securely identify BD lenses based on only event timescales tE because short-timescale events can also be produced by stellar lenses with high relative lens-source proper motions. In this paper, we report three strong candidate BD-lens events found from the search for lensing events not only with short timescales (tE≲6days) but also with very small angular Einstein radii (θE≲0.05mas) among the events that have been found in the 2016-2019 observing seasons. These events include MOA-2017-BLG-147, MOA-2017-BLG-241, and MOA-2019-BLG-256, in which the first two events are produced by single lenses and the last event is produced by a binary lens. From the Monte Carlo simulations of Galactic events conducted with the combined tE and θE constraint, it is estimated that the lens masses of the individual events are 0.051–0.027+0.100M☉, 0.044–0.023+0.090M☉, and 0.046–0.023+0.067M☉/0.038–0.019+0.056M☉ and the probability of the lens mass smaller than the lower limit of stars is ∼80% for all events. We point out that routine lens mass measurements of short-timescale lensing events require survey-mode space-based observations.

Abstract Copyright: © 2020. The American Astronomical Society. All rights reserved.

Journal keyword(s): Gravitational microlensing - Brown dwarfs

Simbad objects: 14

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Number of rows : 14
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 OGLE-2017-BLG-0776 * 17 36 14.7925170541 -27 02 35.988891589     19.56   16.72 ~ 3 0
2 KMT-2016-BLG-1089 * 17 42 23.31 -33 45 35.2           ~ 11 0
3 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
4 OGLE-2011-BLG-0420 * 17 50 56.1715170240 -29 49 30.216419616           ~ 11 1
5 OGLE BLG-LPV-79048 LP* 17 51 51.32856 -30 27 31.3416     19.472   14.966 ~ 10 0
6 OGLE-2017-BLG-0504 * 17 52 09.6478600799 -31 49 13.424460290     19.52   16.59 ~ 3 0
7 OGLE-2016-BLG-0864 * 17 53 12.00 -30 11 32.1           ~ 7 0
8 MOA 2009-BLG-232 * 17 54 22.3539093816 -29 03 21.146804712           ~ 13 1
9 MOA 2015-BLG-281 BD? 17 55 01.020 -29 02 49.60           ~ 22 0
10 OGLE-2016-BLG-0156 * 17 56 36.63 -31 04 40.7           ~ 3 0
11 OGLE-2016-BLG-1540 * 18 00 47.00 -28 21 35.2           ~ 17 0
12 UCAC4 313-136813 * 18 02 11.3080588558 -27 29 51.407681514     17.80   15.32 ~ 3 0
13 OGLE-2016-BLG-1469 BD? 18 07 46.98 -26 17 23.6           ~ 5 0
14 NAME Galactic Bulge reg ~ ~           ~ 4794 0

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