Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf

Yossi Shvartzvald; Jennifer C. Yee; Jan Skowron; Chung-Uk Lee; Andrzej Udalski; Sebastiano Calchi Novati; Valerio Bozza; Charles A. Beichman; Geoffery Bryden; Sean Carey; B. Scott Gaudi; Calen B. Henderson; Wei Zhu; Etienne Bachelet; Greg Bolt; Grant Christie; Dan Maoz; Tim Natusch; Richard W. Pogge; Rachel A. Street; Thiam-Guan Tan; Yiannis Tsapras; Pawel Pietrukowicz; Igor Soszynski; Michal K. Szymanski; Przemek Mróz; Radoslaw Poleski; Szymon Kozlowski; Krzysztof Ulaczyk; Michal Pawlak; Krzysztof A. Rybicki; Patryk Iwanek; Michael D. Albrow; Sang-Mok Cha; Sun-Ju Chung; Andrew Gould; Cheongho Han; Kyu-Ha Hwang; Youn Kil Jung; Dong-Jin Kim; Hyoun-Woo Kim; Seung-Lee Kim; Dong-Joo Lee; Yongseok Lee; Byeong-Gon Park; Yoon-Hyun Ryu; In-Gu Shin; Weicheng Zang; Martin Dominik; Christiane Helling; Markus Hundertmark; Uffe G. Jørgensen; Penelope Longa-Peña; Stephen Lowry; Sedighe Sajadian; Martin J. Burgdorf; Justyn Campbell-White; Simona Ciceri; Daniel F. Evans; Yuri I. Fujii; Tobias C. Hinse; Sohrab Rahvar; Markus Rabus; Jesper Skottfelt; Colin Snodgrass; John Southworth

doi:10.3847/1538-3881/aafe12

Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf

Yossi Shvartzvald, Jennifer C. Yee, Jan Skowron, Chung-Uk Lee, Andrzej Udalski, Sebastiano Calchi Novati, Valerio Bozza, Charles A. Beichman, Geoffery Bryden, Sean Carey, B. Scott Gaudi, Calen B. Henderson, Wei Zhu, Etienne Bachelet, Greg Bolt, Grant Christie, Dan Maoz, Tim Natusch, Richard W. Pogge, Rachel A. StreetThiam-Guan Tan, Yiannis Tsapras, Pawel Pietrukowicz, Igor Soszynski, Michal K. Szymanski, Przemek Mróz, Radoslaw Poleski, Szymon Kozlowski, Krzysztof Ulaczyk, Michal Pawlak, Krzysztof A. Rybicki, Patryk Iwanek, Michael D. Albrow, Sang-Mok Cha, Sun-Ju Chung, Andrew Gould, Cheongho Han, Kyu-Ha Hwang, Youn Kil Jung, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Yoon-Hyun Ryu, In-Gu Shin, Weicheng Zang, Martin Dominik, Christiane Helling, Markus Hundertmark, Uffe G. Jørgensen, Penelope Longa-Peña, Stephen Lowry, Sedighe Sajadian, Martin J. Burgdorf, Justyn Campbell-White, Simona Ciceri, Daniel F. Evans, Yuri I. Fujii, Tobias C. Hinse, Sohrab Rahvar, Markus Rabus, Jesper Skottfelt, Colin Snodgrass, John Southworth

School of Physics and Astronomy

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

Abstract

The kinematics of isolated brown dwarfs in the Galaxy, beyond the solar neighborhood, is virtually unknown. Microlensing has the potential to probe this hidden population, as it can measure both the mass and five of the six phase-space coordinates (all except the radial velocity) even of a dark isolated lens. However, the measurements of both the microlens-parallax and finite-source effects are needed in order to recover the full information. Here, we combine the Spitzer satellite parallax measurement with the ground-based light curve, which exhibits strong finite-source effects, of event OGLE-2017-BLG-0896. We find two degenerate solutions for the lens (due to the known satellite-parallax degeneracy), which are consistent with each other except for their proper motion. The lens is an isolated brown dwarf with a mass of either 18 ± 1 M_J or 20 ± 1 M_J. This is the lowest isolated-object mass measurement to date, only ?45% more massive than the theoretical deuterium-fusion boundary at solar metallicity, which is the common definition of a free-floating planet. The brown dwarf is located at either 3.9 ± 0.1 kpc or 4.1 ± 0.1 kpc toward the Galactic bulge, but with proper motion in the opposite direction of disk stars, with one solution suggesting it is moving within the Galactic plane. While it is possibly a halo brown dwarf, it might also represent a different, unknown population.

Original language	English
Number of pages	17
Journal	Astronomical Journal
Volume	157
Issue number	3
Early online date	11 Feb 2019
DOIs	https://doi.org/10.3847/1538-3881/aafe12
Publication status	Published - Mar 2019

Keywords / Materials (for Non-textual outputs)

galaxy: bulge; gravitational lensing: micro

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10.3847/1538-3881/aafe12

1805.08778.pdf - Snodgrass 87169806Accepted author manuscript, 1.18 MB

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Shvartzvald, Y., Yee, J. C., Skowron, J., Lee, C.-U., Udalski, A., Novati, S. C., Bozza, V., Beichman, C. A., Bryden, G., Carey, S., Gaudi, B. S., Henderson, C. B., Zhu, W., Bachelet, E., Bolt, G., Christie, G., Maoz, D., Natusch, T., Pogge, R. W., ... Southworth, J. (2019). Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf. Astronomical Journal, 157(3). https://doi.org/10.3847/1538-3881/aafe12

@article{5abd3692227d4b6e82b4aacdf35d6813,

title = "Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf",

abstract = "The kinematics of isolated brown dwarfs in the Galaxy, beyond the solar neighborhood, is virtually unknown. Microlensing has the potential to probe this hidden population, as it can measure both the mass and five of the six phase-space coordinates (all except the radial velocity) even of a dark isolated lens. However, the measurements of both the microlens-parallax and finite-source effects are needed in order to recover the full information. Here, we combine the Spitzer satellite parallax measurement with the ground-based light curve, which exhibits strong finite-source effects, of event OGLE-2017-BLG-0896. We find two degenerate solutions for the lens (due to the known satellite-parallax degeneracy), which are consistent with each other except for their proper motion. The lens is an isolated brown dwarf with a mass of either 18 ± 1 MJ or 20 ± 1 MJ. This is the lowest isolated-object mass measurement to date, only ?45% more massive than the theoretical deuterium-fusion boundary at solar metallicity, which is the common definition of a free-floating planet. The brown dwarf is located at either 3.9 ± 0.1 kpc or 4.1 ± 0.1 kpc toward the Galactic bulge, but with proper motion in the opposite direction of disk stars, with one solution suggesting it is moving within the Galactic plane. While it is possibly a halo brown dwarf, it might also represent a different, unknown population.",

keywords = "galaxy: bulge; gravitational lensing: micro",

author = "Yossi Shvartzvald and Yee, {Jennifer C.} and Jan Skowron and Chung-Uk Lee and Andrzej Udalski and Novati, {Sebastiano Calchi} and Valerio Bozza and Beichman, {Charles A.} and Geoffery Bryden and Sean Carey and Gaudi, {B. Scott} and Henderson, {Calen B.} and Wei Zhu and Etienne Bachelet and Greg Bolt and Grant Christie and Dan Maoz and Tim Natusch and Pogge, {Richard W.} and Street, {Rachel A.} and Thiam-Guan Tan and Yiannis Tsapras and Pawel Pietrukowicz and Igor Soszynski and Szymanski, {Michal K.} and Przemek Mr{\'o}z and Radoslaw Poleski and Szymon Kozlowski and Krzysztof Ulaczyk and Michal Pawlak and Rybicki, {Krzysztof A.} and Patryk Iwanek and Albrow, {Michael D.} and Sang-Mok Cha and Sun-Ju Chung and Andrew Gould and Cheongho Han and Kyu-Ha Hwang and Jung, {Youn Kil} and Dong-Jin Kim and Hyoun-Woo Kim and Seung-Lee Kim and Dong-Joo Lee and Yongseok Lee and Byeong-Gon Park and Yoon-Hyun Ryu and In-Gu Shin and Weicheng Zang and Martin Dominik and Christiane Helling and Markus Hundertmark and J{\o}rgensen, {Uffe G.} and Penelope Longa-Pe{\~n}a and Stephen Lowry and Sedighe Sajadian and Burgdorf, {Martin J.} and Justyn Campbell-White and Simona Ciceri and Evans, {Daniel F.} and Fujii, {Yuri I.} and Hinse, {Tobias C.} and Sohrab Rahvar and Markus Rabus and Jesper Skottfelt and Colin Snodgrass and John Southworth",

year = "2019",

month = mar,

doi = "10.3847/1538-3881/aafe12",

language = "English",

volume = "157",

journal = "Astronomical Journal",

issn = "1538-3881",

publisher = "American Astronomical Society",

number = "3",

}

Shvartzvald, Y, Yee, JC, Skowron, J, Lee, C-U, Udalski, A, Novati, SC, Bozza, V, Beichman, CA, Bryden, G, Carey, S, Gaudi, BS, Henderson, CB, Zhu, W, Bachelet, E, Bolt, G, Christie, G, Maoz, D, Natusch, T, Pogge, RW, Street, RA, Tan, T-G, Tsapras, Y, Pietrukowicz, P, Soszynski, I, Szymanski, MK, Mróz, P, Poleski, R, Kozlowski, S, Ulaczyk, K, Pawlak, M, Rybicki, KA, Iwanek, P, Albrow, MD, Cha, S-M, Chung, S-J, Gould, A, Han, C, Hwang, K-H, Jung, YK, Kim, D-J, Kim, H-W, Kim, S-L, Lee, D-J, Lee, Y, Park, B-G, Ryu, Y-H, Shin, I-G, Zang, W, Dominik, M, Helling, C, Hundertmark, M, Jørgensen, UG, Longa-Peña, P, Lowry, S, Sajadian, S, Burgdorf, MJ, Campbell-White, J, Ciceri, S, Evans, DF, Fujii, YI, Hinse, TC, Rahvar, S, Rabus, M, Skottfelt, J, Snodgrass, C & Southworth, J 2019, 'Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf', Astronomical Journal, vol. 157, no. 3. https://doi.org/10.3847/1538-3881/aafe12

TY - JOUR

T1 - Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf

AU - Shvartzvald, Yossi

AU - Yee, Jennifer C.

AU - Skowron, Jan

AU - Lee, Chung-Uk

AU - Udalski, Andrzej

AU - Novati, Sebastiano Calchi

AU - Bozza, Valerio

AU - Beichman, Charles A.

AU - Bryden, Geoffery

AU - Carey, Sean

AU - Gaudi, B. Scott

AU - Henderson, Calen B.

AU - Zhu, Wei

AU - Bachelet, Etienne

AU - Bolt, Greg

AU - Christie, Grant

AU - Maoz, Dan

AU - Natusch, Tim

AU - Pogge, Richard W.

AU - Street, Rachel A.

AU - Tan, Thiam-Guan

AU - Tsapras, Yiannis

AU - Pietrukowicz, Pawel

AU - Soszynski, Igor

AU - Szymanski, Michal K.

AU - Mróz, Przemek

AU - Poleski, Radoslaw

AU - Kozlowski, Szymon

AU - Ulaczyk, Krzysztof

AU - Pawlak, Michal

AU - Rybicki, Krzysztof A.

AU - Iwanek, Patryk

AU - Albrow, Michael D.

AU - Cha, Sang-Mok

AU - Chung, Sun-Ju

AU - Gould, Andrew

AU - Han, Cheongho

AU - Hwang, Kyu-Ha

AU - Jung, Youn Kil

AU - Kim, Dong-Jin

AU - Kim, Hyoun-Woo

AU - Kim, Seung-Lee

AU - Lee, Dong-Joo

AU - Lee, Yongseok

AU - Park, Byeong-Gon

AU - Ryu, Yoon-Hyun

AU - Shin, In-Gu

AU - Zang, Weicheng

AU - Dominik, Martin

AU - Helling, Christiane

AU - Hundertmark, Markus

AU - Jørgensen, Uffe G.

AU - Longa-Peña, Penelope

AU - Lowry, Stephen

AU - Sajadian, Sedighe

AU - Burgdorf, Martin J.

AU - Campbell-White, Justyn

AU - Ciceri, Simona

AU - Evans, Daniel F.

AU - Fujii, Yuri I.

AU - Hinse, Tobias C.

AU - Rahvar, Sohrab

AU - Rabus, Markus

AU - Skottfelt, Jesper

AU - Snodgrass, Colin

AU - Southworth, John

PY - 2019/3

Y1 - 2019/3

N2 - The kinematics of isolated brown dwarfs in the Galaxy, beyond the solar neighborhood, is virtually unknown. Microlensing has the potential to probe this hidden population, as it can measure both the mass and five of the six phase-space coordinates (all except the radial velocity) even of a dark isolated lens. However, the measurements of both the microlens-parallax and finite-source effects are needed in order to recover the full information. Here, we combine the Spitzer satellite parallax measurement with the ground-based light curve, which exhibits strong finite-source effects, of event OGLE-2017-BLG-0896. We find two degenerate solutions for the lens (due to the known satellite-parallax degeneracy), which are consistent with each other except for their proper motion. The lens is an isolated brown dwarf with a mass of either 18 ± 1 MJ or 20 ± 1 MJ. This is the lowest isolated-object mass measurement to date, only ?45% more massive than the theoretical deuterium-fusion boundary at solar metallicity, which is the common definition of a free-floating planet. The brown dwarf is located at either 3.9 ± 0.1 kpc or 4.1 ± 0.1 kpc toward the Galactic bulge, but with proper motion in the opposite direction of disk stars, with one solution suggesting it is moving within the Galactic plane. While it is possibly a halo brown dwarf, it might also represent a different, unknown population.

AB - The kinematics of isolated brown dwarfs in the Galaxy, beyond the solar neighborhood, is virtually unknown. Microlensing has the potential to probe this hidden population, as it can measure both the mass and five of the six phase-space coordinates (all except the radial velocity) even of a dark isolated lens. However, the measurements of both the microlens-parallax and finite-source effects are needed in order to recover the full information. Here, we combine the Spitzer satellite parallax measurement with the ground-based light curve, which exhibits strong finite-source effects, of event OGLE-2017-BLG-0896. We find two degenerate solutions for the lens (due to the known satellite-parallax degeneracy), which are consistent with each other except for their proper motion. The lens is an isolated brown dwarf with a mass of either 18 ± 1 MJ or 20 ± 1 MJ. This is the lowest isolated-object mass measurement to date, only ?45% more massive than the theoretical deuterium-fusion boundary at solar metallicity, which is the common definition of a free-floating planet. The brown dwarf is located at either 3.9 ± 0.1 kpc or 4.1 ± 0.1 kpc toward the Galactic bulge, but with proper motion in the opposite direction of disk stars, with one solution suggesting it is moving within the Galactic plane. While it is possibly a halo brown dwarf, it might also represent a different, unknown population.

KW - galaxy: bulge; gravitational lensing: micro

U2 - 10.3847/1538-3881/aafe12

DO - 10.3847/1538-3881/aafe12

M3 - Article

SN - 1538-3881

VL - 157

JO - Astronomical Journal

JF - Astronomical Journal

IS - 3

ER -

Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf

Abstract

Keywords / Materials (for Non-textual outputs)

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