_version_ 1866916268255215616
author Ruffio, Jean-Baptiste
Perrin, Marshall D.
Hoch, Kielan K. W.
Kammerer, Jens
Konopacky, Quinn M.
Pueyo, Laurent
Madurowicz, Alex
Rickman, Emily
Theissen, Christopher A.
Agrawal, Shubh
Greenbaum, Alexandra Z.
Miles, Brittany E.
Barman, Travis S.
Balmer, William O.
Llop-Sayson, Jorge
Girard, Julien H.
Rebollido, Isabel
Soummer, Rémi
Allen, Natalie H.
Anderson, Jay
Beichman, Charles A.
Bellini, Andrea
Bryden, Geoffrey
Espinoza, Néstor
Glidden, Ana
Huang, Jingcheng
Lewis, Nikole K.
Libralato, Mattia
Louie, Dana R.
Sohn, Sangmo Tony
Seager, Sara
van der Marel, Roeland P.
Wakeford, Hannah R.
Watkins, Laura L.
Ygouf, Marie
Mountai, C. Matt
author_facet Ruffio, Jean-Baptiste
Perrin, Marshall D.
Hoch, Kielan K. W.
Kammerer, Jens
Konopacky, Quinn M.
Pueyo, Laurent
Madurowicz, Alex
Rickman, Emily
Theissen, Christopher A.
Agrawal, Shubh
Greenbaum, Alexandra Z.
Miles, Brittany E.
Barman, Travis S.
Balmer, William O.
Llop-Sayson, Jorge
Girard, Julien H.
Rebollido, Isabel
Soummer, Rémi
Allen, Natalie H.
Anderson, Jay
Beichman, Charles A.
Bellini, Andrea
Bryden, Geoffrey
Espinoza, Néstor
Glidden, Ana
Huang, Jingcheng
Lewis, Nikole K.
Libralato, Mattia
Louie, Dana R.
Sohn, Sangmo Tony
Seager, Sara
van der Marel, Roeland P.
Wakeford, Hannah R.
Watkins, Laura L.
Ygouf, Marie
Mountai, C. Matt
contents The JWST NIRSpec integral field unit (IFU) presents a unique opportunity to observe directly imaged exoplanets from 3-5 um at moderate spectral resolution (R~2,700) and thereby better constrain the composition, disequilibrium chemistry, and cloud properties of their atmospheres. In this work, we present the first NIRSpec IFU high-contrast observations of a substellar companion that requires starlight suppression techniques. We develop specific data reduction strategies to study faint companions around bright stars, and assess the performance of NIRSpec at high contrast. First, we demonstrate an approach to forward model the companion signal and the starlight directly in the detector images, which mitigates the effects of NIRSpec's spatial undersampling. We demonstrate a sensitivity to planets that are 3e-6 fainter than their stars at 1'', or 3e-5 at 0.3''. Then, we implement a reference star point spread function (PSF) subtraction and a spectral extraction that does not require spatially and spectrally regularly sampled spectral cubes. This allows us to extract a moderate resolution (R~2,700) spectrum of the faint T-dwarf companion HD 19467 B from 2.9-5.2 um with signal-to-noise ratio (S/N)~10 per resolution element. Across this wavelength range, HD~19467~B has a flux ratio varying between 1e-5-1e-4 and a separation relative to its star of 1.6''. A companion paper by Hoch et al. more deeply analyzes the atmospheric properties of this companion based on the extracted spectrum. Using the methods developed here, NIRSpec's sensitivity may enable direct detection and spectral characterization of relatively old (~1 Gyr), cool (~250 K), and closely separated (~3-5 au) exoplanets that are less massive than Jupiter.
format Preprint
id arxiv_https___arxiv_org_abs_2310_09902
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle JWST-TST High Contrast: Achieving direct spectroscopy of faint substellar companions next to bright stars with the NIRSpec IFU
Ruffio, Jean-Baptiste
Perrin, Marshall D.
Hoch, Kielan K. W.
Kammerer, Jens
Konopacky, Quinn M.
Pueyo, Laurent
Madurowicz, Alex
Rickman, Emily
Theissen, Christopher A.
Agrawal, Shubh
Greenbaum, Alexandra Z.
Miles, Brittany E.
Barman, Travis S.
Balmer, William O.
Llop-Sayson, Jorge
Girard, Julien H.
Rebollido, Isabel
Soummer, Rémi
Allen, Natalie H.
Anderson, Jay
Beichman, Charles A.
Bellini, Andrea
Bryden, Geoffrey
Espinoza, Néstor
Glidden, Ana
Huang, Jingcheng
Lewis, Nikole K.
Libralato, Mattia
Louie, Dana R.
Sohn, Sangmo Tony
Seager, Sara
van der Marel, Roeland P.
Wakeford, Hannah R.
Watkins, Laura L.
Ygouf, Marie
Mountai, C. Matt
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
The JWST NIRSpec integral field unit (IFU) presents a unique opportunity to observe directly imaged exoplanets from 3-5 um at moderate spectral resolution (R~2,700) and thereby better constrain the composition, disequilibrium chemistry, and cloud properties of their atmospheres. In this work, we present the first NIRSpec IFU high-contrast observations of a substellar companion that requires starlight suppression techniques. We develop specific data reduction strategies to study faint companions around bright stars, and assess the performance of NIRSpec at high contrast. First, we demonstrate an approach to forward model the companion signal and the starlight directly in the detector images, which mitigates the effects of NIRSpec's spatial undersampling. We demonstrate a sensitivity to planets that are 3e-6 fainter than their stars at 1'', or 3e-5 at 0.3''. Then, we implement a reference star point spread function (PSF) subtraction and a spectral extraction that does not require spatially and spectrally regularly sampled spectral cubes. This allows us to extract a moderate resolution (R~2,700) spectrum of the faint T-dwarf companion HD 19467 B from 2.9-5.2 um with signal-to-noise ratio (S/N)~10 per resolution element. Across this wavelength range, HD~19467~B has a flux ratio varying between 1e-5-1e-4 and a separation relative to its star of 1.6''. A companion paper by Hoch et al. more deeply analyzes the atmospheric properties of this companion based on the extracted spectrum. Using the methods developed here, NIRSpec's sensitivity may enable direct detection and spectral characterization of relatively old (~1 Gyr), cool (~250 K), and closely separated (~3-5 au) exoplanets that are less massive than Jupiter.
title JWST-TST High Contrast: Achieving direct spectroscopy of faint substellar companions next to bright stars with the NIRSpec IFU
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2310.09902