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

Spitzer Team, , OGLE Collaboration, KMTNet Collaboration, MiNDSTEp Collaboration, Yossi Shvartzvald (Lead / Corresponding author), 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 BoltGrant Christie, Dan Maoz, Tim Natusch, Richard W. Pogge, Rachel A. Street, Thiam-Guan Tan, Yiannis Tsapras, Paweł Pietrukowicz, Igor Soszyński, Michał K. Szymański, Przemek Mróz, Radoslaw Poleski, Szymon Kozłowski, Krzysztof Ulaczyk, Michał 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, Hyoun-Woo Kim, Seung-Lee Kim, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Yoon-Hyun Ryu, Justyn Campbell-White

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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 languageEnglish
Article number106
Pages (from-to)1-8
Number of pages8
JournalAstronomical Journal
Volume157
Issue number3
Early online date11 Feb 2019
DOIs
Publication statusPublished - Mar 2019

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parallax
counters
lenses
proper motion
galactic bulge
solar neighborhood
deuterium
radial velocity
floating
light curve
metallicity
planets
halos
kinematics
planet
fusion
probe
galaxies
stars
probes

Keywords

  • Galaxy: bulge
  • gravitational lensing: micro

Cite this

Spitzer Team, OGLE Collaboration, KMTNet Collaboration, MiNDSTEp Collaboration, Shvartzvald, Y., ... Campbell-White, J. (2019). Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf. Astronomical Journal, 157(3), 1-8. [106]. https://doi.org/10.3847/1538-3881/aafe12
Spitzer Team ; OGLE Collaboration ; KMTNet Collaboration ; MiNDSTEp Collaboration ; Shvartzvald, Yossi ; Yee, Jennifer C. ; Skowron, Jan ; Lee, Chung-Uk ; Udalski, Andrzej ; Calchi Novati, Sebastiano ; Bozza, Valerio ; Beichman, Charles A. ; Bryden, Geoffery ; Carey, Sean ; Gaudi, B. Scott ; Henderson, Calen B. ; Zhu, Wei ; Bachelet, Etienne ; Bolt, Greg ; Christie, Grant ; Maoz, Dan ; Natusch, Tim ; Pogge, Richard W. ; Street, Rachel A. ; Tan, Thiam-Guan ; Tsapras, Yiannis ; Pietrukowicz, Paweł ; Soszyński, Igor ; Szymański, Michał K. ; Mróz, Przemek ; Poleski, Radoslaw ; Kozłowski, Szymon ; Ulaczyk, Krzysztof ; Pawlak, Michał ; Rybicki, Krzysztof A. ; Iwanek, Patryk ; Albrow, Michael D. ; Cha, Sang-Mok ; Chung, Sun-Ju ; Gould, Andrew ; Han, Cheongho ; Hwang, Kyu-Ha ; Jung, Youn Kil ; Kim, Hyoun-Woo ; Kim, Seung-Lee ; Lee, Dong-Joo ; Lee, Yongseok ; Park, Byeong-Gon ; Ryu, Yoon-Hyun ; Campbell-White, Justyn. / Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf. In: Astronomical Journal. 2019 ; Vol. 157, No. 3. pp. 1-8.
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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.",
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Spitzer Team, OGLE Collaboration, KMTNet Collaboration, MiNDSTEp Collaboration, Shvartzvald, Y, Yee, JC, Skowron, J, Lee, C-U, Udalski, A, Calchi Novati, S, 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, Soszyński, I, Szymański, MK, Mróz, P, Poleski, R, Kozłowski, 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, H-W, Kim, S-L, Lee, D-J, Lee, Y, Park, B-G & Ryu, Y-H & Campbell-White, J 2019, 'Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf', Astronomical Journal, vol. 157, no. 3, 106, pp. 1-8. https://doi.org/10.3847/1538-3881/aafe12

Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf. / Spitzer Team; OGLE Collaboration; KMTNet Collaboration; MiNDSTEp Collaboration; Shvartzvald, Yossi (Lead / Corresponding author); Yee, Jennifer C.; Skowron, Jan; Lee, Chung-Uk; Udalski, Andrzej; Calchi Novati, Sebastiano; Bozza, Valerio; Beichman, Charles A.; Bryden, Geoffery; Carey, Sean; Gaudi, B. Scott; Henderson, Calen B.; Zhu, Wei; Bachelet, Etienne; Bolt, Greg; Christie, Grant; Maoz, Dan; Natusch, Tim; Pogge, Richard W.; Street, Rachel A.; Tan, Thiam-Guan; Tsapras, Yiannis; Pietrukowicz, Paweł; Soszyński, Igor; Szymański, Michał K.; Mróz, Przemek; Poleski, Radoslaw; Kozłowski, Szymon; Ulaczyk, Krzysztof; Pawlak, Michał; Rybicki, Krzysztof A.; Iwanek, Patryk; Albrow, Michael D.; Cha, Sang-Mok; Chung, Sun-Ju; Gould, Andrew; Han, Cheongho; Hwang, Kyu-Ha; Jung, Youn Kil; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Ryu, Yoon-Hyun; Campbell-White, Justyn.

In: Astronomical Journal, Vol. 157, No. 3, 106, 03.2019, p. 1-8.

Research output: Contribution to journalArticle

TY - JOUR

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

AU - Spitzer Team

AU - OGLE Collaboration

AU - KMTNet Collaboration

AU - MiNDSTEp Collaboration

AU - Shvartzvald, Yossi

AU - Yee, Jennifer C.

AU - Skowron, Jan

AU - Lee, Chung-Uk

AU - Udalski, Andrzej

AU - Calchi Novati, Sebastiano

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, Paweł

AU - Soszyński, Igor

AU - Szymański, Michał K.

AU - Mróz, Przemek

AU - Poleski, Radoslaw

AU - Kozłowski, Szymon

AU - Ulaczyk, Krzysztof

AU - Pawlak, Michał

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, Hyoun-Woo

AU - Kim, Seung-Lee

AU - Lee, Dong-Joo

AU - Lee, Yongseok

AU - Park, Byeong-Gon

AU - Ryu, Yoon-Hyun

AU - Campbell-White, Justyn

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 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.

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 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.

KW - Galaxy: bulge

KW - gravitational lensing: micro

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DO - 10.3847/1538-3881/aafe12

M3 - Article

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JO - Astronomical Journal

JF - Astronomical Journal

SN - 0004-6256

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ER -

Spitzer Team, OGLE Collaboration, KMTNet Collaboration, MiNDSTEp Collaboration, Shvartzvald Y et al. Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf. Astronomical Journal. 2019 Mar;157(3):1-8. 106. https://doi.org/10.3847/1538-3881/aafe12