OGLE-2003-BLG-238: Microlensing mass estimate of an isolated star

G F  Jiang; D L  DePoy; A  Gal-Yam; B S  Gaudi; A  Gould; C  Han; Y  Lipkin; D  Maoz; E O  Ofek; B G  Park; R W  Pogge; A  Udalski; M  Kubiak; M K  Szymanski; O  Szewczyk; K  Zerbrun; L  Wyrzykowski; I  Soszynski; G  Pietrzynski; M D  Albrow; J P  Beaulieu; J A R  Caldwell; A  Cassan; C  Coutures; M  Dominik; J  Donatowicz; P  Fouque; J  Greenhill; K  Hill; K  Horne; S F  Jorgensen; U G  Jorgensen; S  Kane; D  Kubas; R  Martin; J  Menzies; K R  Pollard; K C  Sahu; J  Wambsganss; R  Watson; A  Williams

OGLE-2003-BLG-238: Microlensing mass estimate of an isolated star

G F Jiang, D L DePoy, A Gal-Yam, B S Gaudi, A Gould, C Han, Y Lipkin, D Maoz, E O Ofek, B G Park, R W Pogge, A Udalski, M Kubiak, M K Szymanski, O Szewczyk, K Zerbrun, L Wyrzykowski, I Soszynski, G Pietrzynski, M D AlbrowJ P Beaulieu, J A R Caldwell, A Cassan, C Coutures, M Dominik, J Donatowicz, P Fouque, J Greenhill, K Hill, K Horne, S F Jorgensen, U G Jorgensen, S Kane, D Kubas, R Martin, J Menzies, K R Pollard, K C Sahu, J Wambsganss, R Watson, A Williams

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

Abstract

Microlensing is the only known direct method to measure the masses of stars that lack visible companions. In terms of microlensing observables, the mass is given by M (c(2)/4G)(r) over tilde (E)theta(E) and so requires the measurement of both the angular Einstein radius theta(E) and the projected Einstein radius (r) over tilde (E). Simultaneous measurement of these two parameters is extremely rare. Here we analyze OGLE-2003-BLG-238, a spectacularly bright (I-min 10.3), high-magnification (A(max) 170) microlensing event. Pronounced finite-source effects permit a measurement of theta(E) = 650 muas. Although the timescale of the event is only t(E) 38 days, one can still obtain weak constraints on the microlens parallax: 4.4 AU < <(r)over tilde>(E) < 18 AU at the 1 sigma level. Together these two parameter measurements yield a range for the lens mass of 0.36 M-circle dot < M < 1.48 M-circle dot. As was the case for MACHO-LMC-5, the only other single star (apart from the Sun) whose mass has been determined from its gravitational effects, this estimate is rather crude. It does, however, demonstrate the viability of the technique. We also discuss future prospects for single-lens mass measurements.

Original language	English
Pages (from-to)	1307-1315
Number of pages	9
Journal	Astrophysical Journal Letters
Volume	617
Publication status	Published - 20 Dec 2004

Keywords

gravitational lensing
stars : fundamental parameters
SPACE-INTERFEROMETRY-MISSION
GRAVITATIONAL LENSING EXPERIMENT
LARGE-MAGELLANIC-CLOUD
GALACTIC BULGE
EVENTS
PHOTOMETRY
HALO
DEGENERACY
PARALLAXES
CANDIDATES

Cite this

Jiang, G. F., DePoy, D. L., Gal-Yam, A., Gaudi, B. S., Gould, A., Han, C., Lipkin, Y., Maoz, D., Ofek, E. O., Park, B. G., Pogge, R. W., Udalski, A., Kubiak, M., Szymanski, M. K., Szewczyk, O., Zerbrun, K., Wyrzykowski, L., Soszynski, I., Pietrzynski, G., ... Williams, A. (2004). OGLE-2003-BLG-238: Microlensing mass estimate of an isolated star. Astrophysical Journal Letters, 617, 1307-1315.

@article{1ae5462b9db9462da9afe33c3b8806b8,

title = "OGLE-2003-BLG-238: Microlensing mass estimate of an isolated star",

abstract = "Microlensing is the only known direct method to measure the masses of stars that lack visible companions. In terms of microlensing observables, the mass is given by M (c(2)/4G)(r) over tilde (E)theta(E) and so requires the measurement of both the angular Einstein radius theta(E) and the projected Einstein radius (r) over tilde (E). Simultaneous measurement of these two parameters is extremely rare. Here we analyze OGLE-2003-BLG-238, a spectacularly bright (I-min 10.3), high-magnification (A(max) 170) microlensing event. Pronounced finite-source effects permit a measurement of theta(E) = 650 muas. Although the timescale of the event is only t(E) 38 days, one can still obtain weak constraints on the microlens parallax: 4.4 AU < <(r)over tilde>(E) < 18 AU at the 1 sigma level. Together these two parameter measurements yield a range for the lens mass of 0.36 M-circle dot < M < 1.48 M-circle dot. As was the case for MACHO-LMC-5, the only other single star (apart from the Sun) whose mass has been determined from its gravitational effects, this estimate is rather crude. It does, however, demonstrate the viability of the technique. We also discuss future prospects for single-lens mass measurements.",

keywords = "gravitational lensing, stars : fundamental parameters, SPACE-INTERFEROMETRY-MISSION, GRAVITATIONAL LENSING EXPERIMENT, LARGE-MAGELLANIC-CLOUD, GALACTIC BULGE, EVENTS, PHOTOMETRY, HALO, DEGENERACY, PARALLAXES, CANDIDATES",

author = "Jiang, {G F} and DePoy, {D L} and A Gal-Yam and Gaudi, {B S} and A Gould and C Han and Y Lipkin and D Maoz and Ofek, {E O} and Park, {B G} and Pogge, {R W} and A Udalski and M Kubiak and Szymanski, {M K} and O Szewczyk and K Zerbrun and L Wyrzykowski and I Soszynski and G Pietrzynski and Albrow, {M D} and Beaulieu, {J P} and Caldwell, {J A R} and A Cassan and C Coutures and M Dominik and J Donatowicz and P Fouque and J Greenhill and K Hill and K Horne and Jorgensen, {S F} and Jorgensen, {U G} and S Kane and D Kubas and R Martin and J Menzies and Pollard, {K R} and Sahu, {K C} and J Wambsganss and R Watson and A Williams",

year = "2004",

month = dec,

day = "20",

language = "English",

volume = "617",

pages = "1307--1315",

journal = "Astrophysical Journal Letters",

issn = "2041-8205",

publisher = "American Astronomical Society",

}

Jiang, GF, DePoy, DL, Gal-Yam, A, Gaudi, BS, Gould, A, Han, C, Lipkin, Y, Maoz, D, Ofek, EO, Park, BG, Pogge, RW, Udalski, A, Kubiak, M, Szymanski, MK, Szewczyk, O, Zerbrun, K, Wyrzykowski, L, Soszynski, I, Pietrzynski, G, Albrow, MD, Beaulieu, JP, Caldwell, JAR, Cassan, A, Coutures, C, Dominik, M, Donatowicz, J, Fouque, P, Greenhill, J, Hill, K, Horne, K, Jorgensen, SF, Jorgensen, UG, Kane, S, Kubas, D, Martin, R, Menzies, J, Pollard, KR, Sahu, KC, Wambsganss, J, Watson, R & Williams, A 2004, 'OGLE-2003-BLG-238: Microlensing mass estimate of an isolated star', Astrophysical Journal Letters, vol. 617, pp. 1307-1315.

TY - JOUR

T1 - OGLE-2003-BLG-238: Microlensing mass estimate of an isolated star

AU - Jiang, G F

AU - DePoy, D L

AU - Gal-Yam, A

AU - Gaudi, B S

AU - Gould, A

AU - Han, C

AU - Lipkin, Y

AU - Maoz, D

AU - Ofek, E O

AU - Park, B G

AU - Pogge, R W

AU - Udalski, A

AU - Kubiak, M

AU - Szymanski, M K

AU - Szewczyk, O

AU - Zerbrun, K

AU - Wyrzykowski, L

AU - Soszynski, I

AU - Pietrzynski, G

AU - Albrow, M D

AU - Beaulieu, J P

AU - Caldwell, J A R

AU - Cassan, A

AU - Coutures, C

AU - Dominik, M

AU - Donatowicz, J

AU - Fouque, P

AU - Greenhill, J

AU - Hill, K

AU - Horne, K

AU - Jorgensen, S F

AU - Jorgensen, U G

AU - Kane, S

AU - Kubas, D

AU - Martin, R

AU - Menzies, J

AU - Pollard, K R

AU - Sahu, K C

AU - Wambsganss, J

AU - Watson, R

AU - Williams, A

PY - 2004/12/20

Y1 - 2004/12/20

N2 - Microlensing is the only known direct method to measure the masses of stars that lack visible companions. In terms of microlensing observables, the mass is given by M (c(2)/4G)(r) over tilde (E)theta(E) and so requires the measurement of both the angular Einstein radius theta(E) and the projected Einstein radius (r) over tilde (E). Simultaneous measurement of these two parameters is extremely rare. Here we analyze OGLE-2003-BLG-238, a spectacularly bright (I-min 10.3), high-magnification (A(max) 170) microlensing event. Pronounced finite-source effects permit a measurement of theta(E) = 650 muas. Although the timescale of the event is only t(E) 38 days, one can still obtain weak constraints on the microlens parallax: 4.4 AU < <(r)over tilde>(E) < 18 AU at the 1 sigma level. Together these two parameter measurements yield a range for the lens mass of 0.36 M-circle dot < M < 1.48 M-circle dot. As was the case for MACHO-LMC-5, the only other single star (apart from the Sun) whose mass has been determined from its gravitational effects, this estimate is rather crude. It does, however, demonstrate the viability of the technique. We also discuss future prospects for single-lens mass measurements.

AB - Microlensing is the only known direct method to measure the masses of stars that lack visible companions. In terms of microlensing observables, the mass is given by M (c(2)/4G)(r) over tilde (E)theta(E) and so requires the measurement of both the angular Einstein radius theta(E) and the projected Einstein radius (r) over tilde (E). Simultaneous measurement of these two parameters is extremely rare. Here we analyze OGLE-2003-BLG-238, a spectacularly bright (I-min 10.3), high-magnification (A(max) 170) microlensing event. Pronounced finite-source effects permit a measurement of theta(E) = 650 muas. Although the timescale of the event is only t(E) 38 days, one can still obtain weak constraints on the microlens parallax: 4.4 AU < <(r)over tilde>(E) < 18 AU at the 1 sigma level. Together these two parameter measurements yield a range for the lens mass of 0.36 M-circle dot < M < 1.48 M-circle dot. As was the case for MACHO-LMC-5, the only other single star (apart from the Sun) whose mass has been determined from its gravitational effects, this estimate is rather crude. It does, however, demonstrate the viability of the technique. We also discuss future prospects for single-lens mass measurements.

KW - gravitational lensing

KW - stars : fundamental parameters

KW - SPACE-INTERFEROMETRY-MISSION

KW - GRAVITATIONAL LENSING EXPERIMENT

KW - LARGE-MAGELLANIC-CLOUD

KW - GALACTIC BULGE

KW - EVENTS

KW - PHOTOMETRY

KW - HALO

KW - DEGENERACY

KW - PARALLAXES

KW - CANDIDATES

UR - http://www.scopus.com/inward/record.url?scp=13944251768&partnerID=8YFLogxK

M3 - Article

SN - 2041-8205

VL - 617

SP - 1307

EP - 1315

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

ER -

OGLE-2003-BLG-238: Microlensing mass estimate of an isolated star

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Keywords

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