J/ApJ/896/79 HST survey of ONC in H20 1.4um abs. band. I. (Robberto+, 2020)
HST survey of the Orion Nebula Cluster in the H2O 1.4um absorption band.
I. A census of substellar and planetary-mass objects.
Robberto M., Gennaro M., Ubeira Gabellini M.G., Hillenbrand L.A.,
Pacifici C., Ubeda L., Andersen M., Barman T., Bellini A., Da Rio N.,
de Mink S.E., Lodato G., Manara C.F., Platais I., Pueyo L., Strampelli G.M.,
Tan J.C., Testi L.
<Astrophys. J., 896, 79 (2020)>
=2020ApJ...896...79R 2020ApJ...896...79R
ADC_Keywords: Stars, pre-main sequence; YSOs; Photometry, infrared; Colors;
Stars, masses; Effective temperatures; Extinction
Keywords: Pre-main sequence stars ; Brown dwarfs ; Young star clusters
Abstract:
In order to obtain a complete census of the stellar and substellar
population, down to a few MJup in the ∼1Myr old Orion Nebula
Cluster, we used the infrared channel of the Wide Field Camera 3 of
the Hubble Space Telescope with the F139M and F130N filters. These
bandpasses correspond to the 1.4µm H2O absorption feature and an
adjacent line-free continuum region. Out of 4504 detected sources,
3352 (about 75%) appear fainter than m130=14 (Vega mag) in the F130N
filter, a brightness corresponding to the hydrogen- burning limit mass
(M∼0.072M☉) at ∼1Myr. Of these, however, only 742 sources have a
negative F130M-F139N color index, indicative of the presence of H2O
vapor in absorption, and can therefore be classified as bona fide M
and L dwarfs, with effective temperatures T≲2850K at an assumed 1Myr
cluster age. On our color-magnitude diagram (CMD), this population of
sources with H2O absorption appears clearly distinct from the larger
background population of highly reddened stars and galaxies with
positive F130M-F139N color index and can be traced down to the
sensitivity limit of our survey, m130∼21.5, corresponding to a 1Myr
old ∼3MJup planetary-mass object under about 2mag of visual
extinction. Theoretical models of the BT-Settl family predicting
substellar isochrones of 1, 2, and 3 Myr down to ∼1MJup fail to
reproduce the observed H2O color index at M≲20MJup. We perform a
Bayesian analysis to determine extinction, mass, and effective
temperature of each substellar member of our sample, together with its
membership probability.
Description:
The data presented in this paper were obtained as part of the Cycle 22
HST Treasury Program "The Orion Nebula Cluster as a Paradigm of Star
Formation" (GO-13826, P.I. M. Robberto). Observations were carried out
between 2015 February 8 and November 29 using the ACS-WFC and WFC3-IR
cameras in coordinated parallel mode. For the WFC3-IR survey we used
the F139M (λc=1.383um, Δλ=64.3nm) and F130N
(λc=1.300um, Δλ=15.6nm) filters.
Using the source catalog obtained from our 2005 HST Treasury Program
GO-10246 (Robberto+ 2013, J/ApJS/207/10), we combine our near-IR WFC3
data with previous ACS photometry at visible wavelengths.
Cross-matching the two catalogs by assuming a maximum distance of 0.2"
between the celestial coordinates, we find that 2753 ACS sources have
been also detected in our near-IR bands. See Table 3 and Section 4.7.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 81 4504 WFC3-IR photometry of ONC sources
table3.dat 103 2753 Cross-matched ACS-VIS and WFC3-IR photometry
of ONC sources
table4.dat 27 1682 Estimated parameters of the ONC sample
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See also:
J/AJ/111/846 : Orion HST survey (O'Dell+ 1996)
J/ApJ/540/236 : KH photometry of Orion Nebula Cluster (Hillenbrand+, 2000)
J/ApJ/541/977 : HST observations of low-mass stars in IC 348 (Najita+, 2000)
J/ApJ/535/325 : Spectra of normal stars in the J-band (Wallace+ 2000)
J/A+A/396/513 : Stellar Rotation in the Orion Nebula Cluster (Herbst+, 2002)
J/ApJ/573/366 : Infrared photometry of Trapezium cluster (Muench+, 2002)
J/ApJ/593/1093 : IC 348 membership (Luhman+, 2003)
J/MNRAS/361/211 : JHK photometry of brown dwarfs in Orion (Lucas+, 2005)
J/AJ/136/2136 : HST/ACS Atlas of Great Orion Nebula proplyds (Ricci+, 2008)
J/ApJ/722/1092 : Optical photometry of the ONC. II. (Da Rio+, 2010)
J/A+A/534/A10 : HST/NICMOS III imaging in ONC (Andersen+, 2011)
J/A+A/533/A38 : Extinction map of OMC-1 (Scandariato+, 2011)
J/ApJ/748/14 : ONC population data from WFI observations (Da Rio+, 2012)
J/ApJ/755/154 : Mass accretion rates from HST in the ONC (Manara+, 2012)
J/ApJ/753/149 : YSOVAR: six EBs in Orion (Morales-Calderon+, 2012)
J/ApJ/744/6 : SONYC census of VLM objects in NGC1333 (Scholz+, 2012)
J/AJ/146/85 : Spectral types of optical stars in ONC (Hillenbrand+, 2013)
J/ApJS/207/10 : HST Treasury Program on the ONC (Robberto+, 2013)
J/A+A/564/A29 : Optical and NIR photometry in Orion A (Bouy+, 2014)
J/ApJ/782/8 : Spectroscopy of 104 objects in the ONC (Ingraham+, 2014)
J/ApJ/818/59 : IN-SYNC. IV. YSOs in Orion A (Da Rio+, 2016)
J/MNRAS/461/1734 : HAWK-I JHK photom. of the Orion Nebula Cloud (Drass+, 2016)
J/ApJ/826/16 : ALMA and GeMS obs. of the OMC1 region (Eisner+, 2016)
J/ApJS/225/10 : Kinematic analysis of M7-L8 dwarfs (Faherty+, 2016)
J/AJ/154/256 : VLM stars and BDs in Upper Sco using Gaia DR1 (Cook+, 2017)
J/ApJ/834/142 : Gould's Belt Distances Survey. II. OMC (Kounkel+, 2017)
J/A+A/619/A106 : 3D shape of Orion A from Gaia DR2 (Grossschedl+, 2018)
J/AJ/156/84 : APOGEE-2 survey of Orion Complex. II. (Kounkel+, 2018)
J/ApJ/870/32 : Kinematics in young star clusters & assoc. (Kuhn+, 2019)
J/ApJ/881/79 : Flamingos-2 NIR photometry in NGC 2244 (Muzic+, 2019)
J/ApJ/896/81 : HST survey of ONC in H2O abs. band. III. (Strampelli+, 2020)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [1/4504] Sequential running number
6- 14 F9.6 deg RAdeg [83.55/84] Right Ascension (J2000)
16- 24 F9.6 deg DEdeg [-5.72/-5.2] Declination (J2000)
26- 33 F8.2 pix Xpix [209/12177] X pixel position on mosaic
35- 42 F8.2 pix Ypix [852/14540] Y pixel position on mosaic
44- 44 A1 --- l_mag130 Limit flag for saturated in F130N filter
46- 50 F5.2 mag mag130 [5.88/23.27]? HST/WFC3 F130N filter magnitude
52- 55 F4.2 mag e_mag130 [0/2.3] F130N filter magnitude uncertainty
57- 57 A1 --- l_mag139 Limit flag for saturated in F139M filter
59- 63 F5.2 mag mag139 [5.21/22.03]? HST/WFC3 F139M filter magnitude
65- 68 F4.2 mag e_mag139 [0/1.5] F139M filter magnitude uncertainty
70- 74 F5.2 mag color [-2.87/2.69]? F130N-F139M color index
76- 79 F4.2 mag e_color [0/2.5] F130N-F139M color uncertainty
81- 81 I1 --- Ndet [0/6] Number of detections
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Seq [3/4504] Sequential running number
6- 16 F11.8 deg RAdeg [83.55/84] Right Ascension (J2000)
18- 28 F11.8 deg DEdeg [-5.7/-5.2] Declination (J2000)
30 A1 --- l_F775W Upper or lower limit flag on F775W (1)
32- 37 F6.3 mag F775W [13.1/81.2] HST/ACS F775W filter magnitude (2)
39- 44 F6.3 mag e_F775W [0.002/84.2]? F775W uncertainty (2)
46 A1 --- l_F850LP Upper or lower limit flag on F850LP (1)
48- 53 F6.3 mag F850LP [12.1/82.6] HST/ACS F850LP filter magnitude (2)
55- 60 F6.3 mag e_F850LP [0.002/84.4]? F850LP uncertainty (2)
62- 62 A1 --- l_mag130 Limit flag for saturated in F130N filter
64- 69 F6.3 mag mag130 [5.87/22.7] HST/WFC3 F130N filter magnitude
71- 75 F5.3 mag e_mag130 [0/1.1] mag130 uncertainty
77- 77 A1 --- l_mag139 Limit flag for saturated in F139M filter
79- 84 F6.3 mag mag139 [5.2/21.67] HST/WFC3 F139M filter magnitude
86- 90 F5.3 mag e_mag139 [0/0.9] mag139 uncertainty
92- 97 F6.3 mag color [-0.86/1.03] F130N-F139M color index
99-103 F5.3 mag e_color [0/1.1] F130N-F139M color uncertainty
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Note (1): An upper limit indicates a magnitude value below the detection limit
whereas a lower limit refers to a saturated star brighter than
the reported magnitude.
Note (2): In order to account for variability, Table 5 of
Robberto+ (2013, J/ApJS/207/10) reports the magnitudes of each
individual detection. To compile this table we have taken the average
magnitudes when multiple values have been reported.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [1/4495] Sequential running number
6- 10 F5.2 [-] log(BF) [-0.5/2] Logarithm of the Bayes Factor (1)
12- 15 F4.2 Msun Mstar [0/1.4] Mass
17- 20 I4 K Teff [671/4182] Effective Temperature
22- 27 F6.2 mag Av [-73.9/30] Extinction estimated using
distance from IR isochrone
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Note (1): Our threshold for declaring a source an ONC candidate, i.e., showing
some evidence that it may not belong to the background population,
corresponds to logarithms of the Bayes factor >-0.5. Bona fide cluster
members have Bayes factor >1.
See Section 4.10.
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History:
From electronic version of the journal
References:
Strampelli et al. Paper I. 2020ApJ...896...79S 2020ApJ...896...79S This Catalog
Gennaro et al. Paper II. 2020ApJ...896...80G 2020ApJ...896...80G
Strampelli et al. Paper III. 2020ApJ...896...81S 2020ApJ...896...81S Cat. J/ApJ/896/81
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Oct-2021