TY - JOUR
T1 - Multiband GPI Imaging of the HR 4796A Debris Disk
AU - Chen, Christine
AU - Mazoyer, Johan
AU - Poteet, Charles A.
AU - Ren, Bin
AU - Duch ne, Gaspard
AU - Hom, Justin
AU - Arriaga, Pauline
AU - Millar-Blanchaer, Maxwell A.
AU - Arnold, Jessica
AU - Bailey, Vanessa P.
AU - Bruzzone, Juan Sebastián
AU - Chilcote, Jeffrey
AU - Choquet, lodie
AU - De Rosa, Robert J.
AU - Draper, Zachary H.
AU - Esposito, Thomas M.
AU - Fitzgerald, Michael P.
AU - Follette, Katherine B.
AU - Hibon, Pascale
AU - Hines, Dean C.
AU - Kalas, Paul
AU - Marchis, Franck
AU - Matthews, Brenda
AU - Milli, Julien
AU - Patience, Jennifer
AU - Perrin, Marshall D.
AU - Pueyo, Laurent
AU - Rajan, Abhijith
AU - Rantakyrö, Fredrik T.
AU - Rodigas, Timothy J.
AU - Roudier, Gael M.
AU - Schneider, Glenn
AU - Soummer, Rémi
AU - Stark, Christopher
AU - Wang, Jason J.
AU - Ward-Duong, Kimberly
AU - Weinberger, Alycia J.
AU - Wilner, David J.
AU - Wolff, Schuyler
N1 - Publisher Copyright:
© 2020. The American Astronomical Society. All rights reserved.
PY - 2020/7/20
Y1 - 2020/7/20
N2 - We have obtained Gemini Planet Imager (GPI) J-, H-, K1-, and K2-Spec observations of the iconic debris ring around the young, main-sequence star HR 4796A. We applied several point-spread function (PSF) subtraction techniques to the observations (Mask-and-Interpolate, RDI-NMF, RDI-KLIP, and ADI-KLIP) to measure the geometric parameters and the scattering phase function for the disk. To understand the systematic errors associated with PSF subtraction, we also forward-modeled the observations using a Markov Chain Monte Carlo framework and a simple model for the disk. We found that measurements of the disk geometric parameters were robust, with all of our analyses yielding consistent results; however, measurements of the scattering phase function were challenging to reconstruct from PSF-subtracted images, despite extensive testing. As a result, we estimated the scattering phase function using disk modeling. We searched for a dependence of the scattering phase function with respect to the GPI filters but found none. We compared the H-band scattering phase function with that measured by Hubble Space Telescope STIS at visual wavelengths and discovered a blue color at small scattering angles and a red color at large scattering angles, consistent with predictions and laboratory measurements of large grains. Finally, we successfully modeled the SPHERE H2 HR 4796A scattered phase function using a distribution of hollow spheres composed of silicates, carbon, and metallic iron.
AB - We have obtained Gemini Planet Imager (GPI) J-, H-, K1-, and K2-Spec observations of the iconic debris ring around the young, main-sequence star HR 4796A. We applied several point-spread function (PSF) subtraction techniques to the observations (Mask-and-Interpolate, RDI-NMF, RDI-KLIP, and ADI-KLIP) to measure the geometric parameters and the scattering phase function for the disk. To understand the systematic errors associated with PSF subtraction, we also forward-modeled the observations using a Markov Chain Monte Carlo framework and a simple model for the disk. We found that measurements of the disk geometric parameters were robust, with all of our analyses yielding consistent results; however, measurements of the scattering phase function were challenging to reconstruct from PSF-subtracted images, despite extensive testing. As a result, we estimated the scattering phase function using disk modeling. We searched for a dependence of the scattering phase function with respect to the GPI filters but found none. We compared the H-band scattering phase function with that measured by Hubble Space Telescope STIS at visual wavelengths and discovered a blue color at small scattering angles and a red color at large scattering angles, consistent with predictions and laboratory measurements of large grains. Finally, we successfully modeled the SPHERE H2 HR 4796A scattered phase function using a distribution of hollow spheres composed of silicates, carbon, and metallic iron.
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U2 - 10.3847/1538-4357/ab9aba
DO - 10.3847/1538-4357/ab9aba
M3 - Article
AN - SCOPUS:85088938238
SN - 0004-637X
VL - 898
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 55
ER -