J/AJ/168/215 Coronographic observations for M dwarfs companions (Sanghi+, 2024)
Efficiently searching for close-in companions around young M dwarfs using a
multiyear PSF library.
Sanghi A., Xuan J.W., Wang J.J., Mawet D., Bowler B.P., Ngo H.,
Bryan M.L., Ruane G., Absil O., Huby E.
<Astron. J., 168, 215 (2024)>
=2024AJ....168..215S 2024AJ....168..215S
ADC_Keywords: Exoplanets ; Stars, dwarfs ; Stars, M-type ; Infrared ; Optical
Keywords: Exoplanet astronomy ; Exoplanet detection methods ; Direct imaging ;
High angular resolution ; Extrasolar gaseous giant planets
Abstract:
We present Super-RDI, a unique framework for the application of
reference star differential imaging (RDI) to Keck/NIRC2 high-contrast
imaging observations with the vortex coronagraph. Super-RDI combines
frame selection and signal-to-noise ratio (S/N) optimization
techniques with a large multiyear reference point-spread function (PSF)
library to achieve optimal PSF subtraction at small angular
separations. We compile a ∼7000 frame reference PSF library based on a
set of 288 new Keck/NIRC2 L' sequences of 237 unique targets acquired
between 2015 and 2019 as part of two planet-search programs designed
for RDI, one focusing on nearby young M dwarfs and the other targeting
members of the Taurus star-forming region. For our data set, synthetic
companion injection-recovery tests reveal that frame selection with
the mean-squared error metric combined with Karhunen-Loeve
Image-Processing-based PSF subtraction using 1000-3000 frames and
<500 principal components yields the highest average S/N for injected
synthetic companions. We uniformly reduce targets in the young M-star
survey with both Super-RDI and angular differential imaging (ADI). For
the typical parallactic angle rotation of our data set (∼10°),
Super-RDI performs better than a widely used implementation of
ADI-based PSF subtraction at separations ≤0.4" (~=5λ/D),
gaining an average of 0.25mag in contrast at 0.25" and 0.4mag in
contrast at 0.15". This represents a performance improvement in
separation space over RDI with single-night reference star
observations (∼100 frame PSF libraries) applied to a similar
Keck/NIRC2 data set in previous work. We recover two known brown dwarf
companions and provide detection limits for 155 targets in the young
M-star survey. Our results demonstrate that increasing the PSF library
size with careful selection of reference frames can improve the
performance of RDI with the Keck/NIRC2 vortex coronagraph in L'.
Description:
This work's sample consists of a set of 288 sequences of 237 unique
targets observed from 2015 December 26 to 2019 January 9. The sample
is comprised of targets that have been observed independently as part
of two survey programs with Keck/NIRC2 near-infrared imager on Mauna
Kea, Hawaii: the young M-star survey (195 observations of 157 unique
targets) and the Taurus survey (93 observations of 80 unique targets).
Both sets of observations were taken with the vector vortex
coronagraph, installed in the Keck/NIRC2 camera, using the QACITS
automatic, real-time coronagraphic PSF centering algorithm
(Huby+ 2015A&A...584A..74H 2015A&A...584A..74H, 2017A&A...600A..46H 2017A&A...600A..46H). The full data set
contains images taken in the L' (central wavelength of 3.776um)
bandpass. For our sample, the median and mean on-source integration
times (number of science frames x coadds x exposure time per coadd)
are 15.0min and 16.5min, respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 133 288 Keck/NIRC2 L' vortex coronagraphic observations
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See also:
III/198 : Palomar/MSU nearby star spectroscopic survey (Hawley+ 1997)
II/237 : Stellar Photometry in Johnson's 11-color syst. (Ducati, 2002)
I/284 : The USNO-B1.0 Catalog (Monet+ 2003)
I/298 : LSPM-North Catalog (Lepine+ 2005)
II/281 : 2MASS 6X Point Source Working Database / Cat. (Cutri+ 2006)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
I/322 : UCAC4 Catalogue (Zacharias+, 2012)
II/328 : AllWISE Data Release (Cutri+ 2013)
J/A+A/403/247 : Variability in ROSAT All-Sky Survey (Fuhrmeister+, 2003)
J/AJ/126/2048 : NStars project: the Northern Sample. I. (Gray+, 2003)
J/other/ARA+A/42.685 : Young stars near the Sun (Zuckerman+, 2004)
J/ApJ/647/1180 : Infrared photometry of Taurus SFR (Luhman+, 2006)
J/AJ/132/866 : New M dwarfs in solar neighborhood (Riaz+, 2006)
J/ApJS/168/128 : UBVRcIc photometry of FHB & metal-poor stars (Beers+, 2007)
J/ApJ/670/1367 : Gemini Deep Planet Survey (Lafreniere+, 2007)
J/ApJ/658/480 : Pre-MS stars in Lupus association (Makarov+, 2007)
J/A+A/467/785 : SuperWASP/ROSAT periodic variable stars (Norton+, 2007)
J/AJ/133/2825 : Star beyond the NLTT catalog (Reid+, 2007)
J/MNRAS/389/585 : Fundamental parameters of M dwarfs (Casagrande+, 2008)
J/AJ/135/850 : Properties of eclipsing binaries in TrES (Devor+, 2008)
J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)
J/AJ/137/4186 : UBVRI standards around celestial equator (Landolt, 2009)
J/ApJ/699/649 : Young M dwarfs within 25pc. I. (Shkolnik+, 2009)
J/MNRAS/403/1949 : UBV(RcIc)JHK photometry of HIP nearby stars (Koen+, 2010)
J/ApJ/731/8 : Multiple star formation in Taurus-Auriga (Kraus+, 2011)
J/AJ/141/97 : SDSS DR7 M dwarfs (West+, 2011)
J/AJ/143/80 : Low-mass stars: beta Pic & AB Dor groups (Schlieder+, 2012)
J/ApJ/758/56 : Young M dwarfs within 25pc.II. Kinematics (Shkolnik+, 2012)
J/A+A/544/A9 : The International Deep Planet Survey. I. (Vigan+, 2012)
J/ApJ/762/88 : Young stellar kinema. group candidate members (Malo+, 2013)
J/ApJ/795/161 : Activity & rotation in Praesepe & Hyades (Douglas+, 2014)
J/ApJ/784/126 : IR phot. of all known members in Taurus (Esplin+, 2014)
J/MNRAS/443/2561 : CONCH-SHELL catalog of nearby M dwarfs (Gaidos+, 2014)
J/AJ/147/146 : Spectroscopy of Tuc-Hor candidate members (Kraus+, 2014)
J/ApJ/788/81 : BANYAN III. RVel & rotation of low-mass stars (Malo+, 2014)
J/AJ/147/85 : Solar neighborhood. XXXIII. 45 M dwarfs (Riedel+, 2014)
J/ApJ/794/146 : M dwarfs with IR excess (Theissen+, 2014)
J/ApJ/798/41 : GALEX NUV obs. of bright M-type stars (Ansdell+, 2015)
J/MNRAS/454/593 : Young moving groups in solar neighbourhood (Bell+, 2015)
J/ApJS/216/7 : Planets Around Low-Mass Stars (PALMS). IV. (Bowler+, 2015)
J/ApJ/799/155 : Sub-stellar companions in Taurus (Daemgen+, 2015)
J/ApJS/219/33 : BANYAN. VII. Candidate YMG members from BASS (Gagne+, 2015)
J/other/Sci/350.64 : 51 Eri b near-infrared spectrum (Macintosh+, 2015)
J/A+A/590/A13 : New candidate members in young assoc. (Elliott+, 2016)
J/ApJ/838/150 : The Taurus-Auriga ecosystem. I. (Kraus+, 2017)
J/AJ/154/129 : PSYM-WIDE: planet.-mass compan. to YMG memb. (Naud+, 2017)
J/MNRAS/475/1960 : ESPaDOnS spectropolarimeter obs.: M dwarfs (Fouque+, 2018)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/AJ/156/286 : The LEECH exoplanet imaging survey (Stone+, 2018)
J/ApJ/877/60 : YMGs. I. Young binaries & Li-rich stars (Bowler+, 2019)
J/ApJ/879/100 : K2 rot. per. for Hyades & Praesepe members (Douglas+, 2019)
J/ApJ/881/9 : EvryFlare.I. Cool stars flares in south sky (Howard+, 2019)
J/AJ/158/13 : The first 300 stars observed by the GPIES (Nielsen+, 2019)
J/ApJS/247/44 : Mira-like variables from the KELT survey (Arnold+, 2020)
J/AJ/159/63 : AO obs. exoplanets & brown dwarf compan. (Bowler+, 2020)
J/A+A/651/A70 : SHINE sample definition (Desidera+, 2021)
J/AJ/161/277 : Sample of 45 HαEW outliers (Kiman+, 2021)
J/A+A/645/A30 : SB updated census in SACY sample (Zuniga-Fernandez+, 2021)
J/AJ/165/39 : CHARIS & SPHERE/IFS IR sp. of HIP 21152 (Franson+, 2023)
J/A+A/672/A93 : AF Lep b spectrum (Mesa+, 2023)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- Set [1/2] Type code (1)
3- 31 A29 --- Name Object identifier
33- 34 I2 h RAh [0/23]? Hour of Right Ascension (J2000)
36- 37 I2 min RAm ? Minute of Right Ascension (J2000)
39- 45 F7.4 s RAs ? Second of Right Ascension (J2000)
47 A1 --- DE- Sign of the Declination (J2000)
49- 50 I2 deg DEd [0/69]? Degree of Declination (J2000)
52- 53 I2 arcmin DEm ? Arcminute of Declination (J2000)
55- 60 F6.3 arcsec DEs ? Arcsecond of Declination (J2000)
62- 71 A10 "Y/M/D" Date Observation date (UT)
73- 81 A9 --- NxCoadds Number of science frames x Coadds (2)
83- 86 F4.2 s Texp Exposure time per coadd (2)
88- 92 F5.1 deg DelPA [0.1/221] Parallactic angle rotation
94- 97 F4.2 arcsec Seeing [0.4/1.4]? Seeing (3)
99- 102 F4.2 arcsec e_Seeing [0.1/0.5]? Uncertainty in Seeing
104- 109 F6.3 mag W1mag [3.2/10.5]? WISE W1 band apparent magnitude
from AllWISE (II/328) unless flagged
111- 115 F5.3 mag e_W1mag [0.02/0.45]? Uncertainty in W1mag
117 A1 --- r_W1mag [a] a: from WISE (II/311)
119- 124 F6.3 mag Rmag [6.9/15.1]? Apparent R band magnitude
126- 130 F5.3 mag e_Rmag [1e-3/0.7]? Uncertainty in Rmag
132- 133 I2 --- r_Rmag [1/20]? Reference code for Rmag (4)
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Note (1): Type as follows:
1 = Young M-star Survey Targets
2 = Taurus Survey Targets. The Taurus survey targets only serve as
reference stars for Super-RDI reductions of the young M-star survey
targets. PSF subtraction of the Taurus survey targets will be
presented in Bryan+ (in preparation).
Note (2): The total integration time is given by:
Tint[s] = N x coadds x Texp[s]
Note (3): The mean and standard deviation of seeing measurements for the night
are presented as recorded by the DIMM Seeing Monitor. Seeing
measurements quoted without uncertainties correspond to approximate
values measured by the CFHT WX Tower Seeing Monitor.
Note (4): Reference code as follows:
1 = Zacharias+ 2012 (I/322); 124 occurrences
2 = Riedel+ 2014 (J/AJ/147/85); 9 occurrences
3 = Norton+ 2007 (J/A+A/467/785); 12 occurrences
4 = Beers+ 2007 (J/ApJS/168/128); 1 occurrence
5 = Lepine & Shara 2005 (I/298); 1 occurrence
6 = Zacharias+ 2009 (I/315); 5 occurrences
7 = Koen+ 2010 (J/MNRAS/403/1949); 4 occurrences
8 = Landolt 2009 (J/AJ/137/4186); 1 occurrence
9 = Zacharias+ 2004 (I/289); 18 occurrences
10 = Makarov+ 2007 (J/ApJ/658/480); 1 occurrence
11 = Reid+ 2007 (J/AJ/133/2825); 2 occurrences
12 = Monet+ 2003 (I/284); 4 occurrences
13 = Casagrande+ 2008 (J/MNRAS/389/585); 2 occurrences
14 = Ducati 2002 (II/237); 3 occurrences
15 = Devor+ 2008 (J/AJ/135/850); 2 occurrences
16 = Kundurthy+ (2006AJ....132.2469K 2006AJ....132.2469K); 4 occurrences
17 = Mendigutia+ (2012A&A...543A..59M 2012A&A...543A..59M); 3 occurrences
18 = Arnold+ 2020 (J/ApJS/247/44); 1 occurrence
19 = Tannirkulam+ (2008ApJ...689..513T 2008ApJ...689..513T); 1 occurrence
20 = Cieza+ (2012ApJ...750..157C 2012ApJ...750..157C); 1 occurrence
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History:
From electronic version of the journal
(End) Prepared by [AAS], Robin Leichtnam [CDS] 26-Jun-2025