Speckle suppression and companion detection using coherent differential imaging

Bottom, Michael; Wallace, J. Kent; Bartos, Randy; Shelton, J. C.; Serabyn, Eugene

doi:10.1093/mnras/stw2544

Cited by 56 publications

(36 citation statements)

References 27 publications

(32 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(v) collapsing residual frames (obtained after PCA modeling and subtraction) using either a simple median or a variance-based weighted average (Bottom et al 2017), for both the PCA-ADI and PCA-SDI parts. For this purpose, we implemented the SDI equivalent of the algorithm presented for ADI residuals in Bottom et al (2017).…”

Section: Algorithm Descriptionmentioning

confidence: 99%

Separating extended disc features from the protoplanet in PDS 70 using VLT/SINFONI

Christiaens

Casassus

Absil

et al. 2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Transition discs are prime targets to look for protoplanets and study planet-disc interactions. We present VLT/SINFONI observations of PDS 70, a transition disc with a recently claimed embedded protoplanet. We take advantage of the angular and spectral diversity present in our data for an optimal PSF modeling and subtraction using principal component analysis (PCA). We report the redetection of PDS 70 b, both the front and far side of the outer disc edge, and the detection of several extended features in the annular gap. We compare spectral differential imaging applied before (PCA-SADI), and after (PCA-ASDI) angular differential imaging. Our tests suggest that PCA-SADI better recovers extended features, while PCA-ASDI is more sensitive to point sources. We adapted the negative fake companion (NEGFC) technique to infer the astrometry of the companion, and derived r = 193.5±4.9 mas and PA = 158.7 • ±3.0 • . We used both NEGFC and ANDROMEDA to infer the K-band spectro-photometry of the protoplanet, and found results consistent with recent VLT/SPHERE observations, except for their 2018/02 epoch measurement in the K2 filter. Finally, we derived anR Jup M Jup yr −1 for the accretion rate of the companion based on an adaptation of PCA-SADI/PCA-ASDI around the Brγ line (assuming no extinction).

show abstract

Section: Algorithm Descriptionmentioning

confidence: 99%

Separating extended disc features from the protoplanet in PDS 70 using VLT/SINFONI

Christiaens

Casassus

Absil

et al. 2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…Doing so means measuring the electric field associated with the stellar speckle in that plane. To do so, Bottom et al (2017) implemented a phase-shifting interferometer on the SDC to spatially modulate the speckle intensity. In this paper, we present the results obtained when implementing a selfcoherent camera (SCC).…”

Section: Principle Of the Self-coherent Cameramentioning

confidence: 99%

“…They are however limited by speckles with lifetime shorter than few minutes (the speckle pattern then changes between the science target and the reference star). Other techniques can do focal plane wavefront sensing and correction (Martinache et al 2014;Bottom et al 2016a;Cady et al 2013;Matthews et al 2017;Bottom et al 2017). Most of them use a temporal modulation of the speckle intensity and they cannot calibrate the speckles with lifetime shorter than the time needed for calibration (usually 4 to 5 images, meaning few minutes for a typical star magnitude).…”

Section: Comparison With Other Techniquesmentioning

confidence: 99%

Minimization of non-common path aberrations at the Palomar telescope using a self-coherent camera

Galicher

Baudoz

Delorme

et al. 2019

A&A

Self Cite

View full text Add to dashboard Cite

Context. The two main advantages of exoplanet imaging are the discovery of objects in the outer part of stellar systems -constraining the models of planet formation -, and its ability to spectrally characterize the planets -giving information on their atmosphere. It is, however, challenging, because exoplanets are up to 10 10 times fainter than their star and separated by a fraction of arcsecond. Current instruments like SPHERE/VLT or GPI/Gemini detect young and massive planets, because they are limited by non-common path aberrations (NCPA) that are not corrected by the adaptive optics system. To probe fainter exoplanets, a new class of instruments capable of minimizing the NCPA is needed. One solution is the self-coherent camera (SCC) focal plane wavefront sensor, whose performance was demonstrated in laboratory attenuating the starlight by factors up to several 10 8 in space-like conditions at angular separations down to 2 λ/D. Aims. In this paper, we demonstrate the SCC on the sky for the first time. Methods. We installed an SCC on the stellar double coronagraph (SDC) instrument at the Hale telescope. We used an internal source to minimize the NCPA that limited the vortex coronagraph performance. We then compared to the standard procedure used at Palomar. Results. On internal source, we demonstrated that the SCC improves the coronagraphic detection limit by a factor between 4 and 20 between 1.5 and 5 λ/D. Using this SCC calibration, the on-sky contrast is improved by a factor of 5 between 2 and 4 λ/D. These results prove the ability of the SCC to be implemented in an existing instrument. Conclusions. This paper highlights two interests of the self-coherent camera. First, the SCC can minimize the speckle intensity in the field of view especially the ones that are very close to the star where many exoplanets are to be discovered. Then, the SCC has a 100% efficiency with science time as each image can be used for both science and NCPA minimization.

show abstract

“…In terms of achievable contrast and detection limits of low-mass companions, Figure 6a shows a typical 5-sigma contrast curve -but under sub-optimal seeing conditions of ~1''.5 -after RDI PCA reduction as described in section §2.3, for a bright (K A ~ 4.5) binary, with a K ~ 2 secondary component at ~ 0''.3 from the primary. No speckle nulling techniques 26 were used here, as it would further impact the observing efficiency ( Fig.3), but those might be valuable to investigate for follow-up observations of candidates in the near future. Also shown on Figure 6a with the second vertical axis are the corresponding mass sensitivity limits in M Jup , based on evolutionary models.…”

Section: Typical On-sky Instrumental Performancementioning

confidence: 99%

High-contrast imaging of tight resolved binaries with two vector vortex coronagraphs in cascade with the Palomar SDC instrument

Kühn

Daemgen

Wang

et al. 2018

Ground-Based and Airborne Instrumentation for Astronomy VII

View full text Add to dashboard Cite

More than half of the stars in the solar neighborhood reside in binary/multiple stellar systems, and recent studies suggest that gas giant planets may be more abundant around binaries than single stars. Yet, these multiple systems are usually overlooked or discarded in most direct imaging surveys, as they prove difficult to image at high-contrast using coronographs. This is particularly the case for compact binaries (less than 1'' angular separation) with similar stellar magnitudes, where no existing coronagraph can provide high-contrast regime. Here we present preliminary results of an on-going Palomar pilot survey searching for low-mass companions around ~15 young "challenging" binary systems, with angular separation as close as 0''3 and near-equal K-band magnitudes. We use the Stellar Double Coronagraph (SDC) instrument on the 200-inch Telescope in a modified optical configuration, making it possible to align any targeted binary system behind two vector vortex coronagraphs in cascade. This approach is uniquely possible at Palomar, thanks to the absence of sky rotation combined with the availability of an extreme AO system, and the number of intermediate focalplanes provided by the SDC instrument. Finally, we expose our current data reduction strategy, and we attempt to quantify the exact contrast gain parameter space of our approach, based on our latest observing runs.

show abstract

Speckle suppression and companion detection using coherent differential imaging

Cited by 56 publications

References 27 publications

Separating extended disc features from the protoplanet in PDS 70 using VLT/SINFONI

Separating extended disc features from the protoplanet in PDS 70 using VLT/SINFONI

Minimization of non-common path aberrations at the Palomar telescope using a self-coherent camera

High-contrast imaging of tight resolved binaries with two vector vortex coronagraphs in cascade with the Palomar SDC instrument

Contact Info

Product

Resources

About