J/A+A/686/A171 Ultracool dwarfs in Euclid Deep Fields (Zhang+, 2024)
Reconnaissance ultracool spectra in the Euclid Deep Fields.
Zhang J.-Y., Lodieu N., Martin E.L.
<Astron. Astrophys. 686, A171 (2024)>
=2024A&A...686A.171Z 2024A&A...686A.171Z (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type ; Stars, brown dwarf ; Photometry, infrared ;
Optical
Keywords: catalogs - surveys - brown dwarfs - stars: late-type - stars: low-mass
Abstract:
The Euclid spacecraft has been launched and will carry out a deep
survey benefiting the discovery and characterisation of ultracool
dwarfs (UCDs), especially in the Euclid Deep Fields (EDFs), which the
telescope will scan repeatedly throughout its mission. The photometric
and spectroscopic standards in the EDFs are important benchmarks,
crucial for the classification and characterisation of new UCD
discoveries and for the calibration of the mission itself.
We aim to provide a list of photometric UCD candidates and collect
near-infrared reconnaissance spectra for M, L, and T-type UCDs in the
EDFs as future Euclid UCD references.
In EDF North, we cross-matched public optical and infrared surveys
with certain photometric criteria to select UCDs. In EDF Fornax and
EDF South, we used photometrically classified samples from the
literature. We also include UCDs identified by Gaia DR2. We selected
seven UCD targets with different spectral types from the lists and
obtained low-resolution 0.9-2.5um spectra of them using GTC/EMIR and
the VLT/X-shooter. We also selected a young, bright L dwarf near EDF
Fornax to test the coherence of these two facilities. We included one
extra T dwarf in EDF North with its published J-band spectrum.
We retrieved a list of 81 (49, 231) M, eight (29, 115) L, and
one (0, 2) T dwarf candidates in EDF North, Fornax, and South,
respectively. They are provided to guide future UCD discoveries and
characterisations by Euclid. In total, we collected near-infrared
spectra for nine UCDs, including two M types, three L types, and four
T types in or close to the three EDFs. The Euclidised spectra show
consistency in their spectral classification, which demonstrates that
slitless Euclid spectroscopy will recover the spectral types with high
fidelity for UCDs, both in the EDFs and in the wide survey. We also
demonstrate that Euclid will be able to distinguish different age
groups of UCDs.
Description:
Euclid, a space-borne telescope dedicated to cosmology, will also be
powerful for UCD science. It has advantages compared with other
current space telescopes, especially the combination of its big FoV
and its depth in the NIR range. It will start nominal surveys soon and
will visit the three EDFs repeatedly. In this work, we provide a list
of UCDs in the three EDFs for Euclid to characterise them and use them
as references to identify new UCDs. We found 81 (49, 231) M, eight
(29, 115) L, and one (0, 2) T dwarfs in EDFs North, Fornax, and South,
respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 114 81 81 late-M-type UCD candidates as photometric
standards in EDF North and their photometry
measurements
tablea2.dat 114 8 Eight L-type UCD candidates as photometric standards
in the EDF North and their photometry measurements
tableb1.dat 122 49 49 M-type UCD candidates as photometric standards
in EDF Fornax and their photometry measurements
tableb2.dat 122 29 29 L-type UCD candidates as photometric standards
in the EDF Fornax and their photometry measurements
tablec1.dat 122 231 231 late-M-type UCD candidates as photometric
standards in EDF South and their photometry
measurements
tablec2.dat 122 68 115 L-type UCD candidates as photometric standards
in EDF South and their photometry measurements
tablec3.dat 122 2 Two T-type UCD candidates as photometric standards
in the EDF South and their photometry measurements
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See also:
J/MNRAS/489/5301 : DES Y3 substellar LT and M catalogs (Carnero Rosell+, 2019)
J/A+A/619/L8 : Ultra-cool dwarfs candidates in Gaia DR2 (Reyle, 2018)
Byte-by-byte Description of file: tablea1.dat tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Note [C *] Note (1)
4- 5 I2 h RAh Right ascension (J2000)
7- 8 I2 min RAm Right ascension (J2000)
10- 14 F5.2 s RAs Right ascension (J2000)
16 A1 --- DE- Declination sign (J2000)
17- 18 I2 deg DEd Declination (J2000)
20- 21 I2 arcmin DEm Declination (J2000)
23- 26 F4.1 arcsec DEs Declination (J2000)
28- 32 F5.2 mag imag DES i magnitude
34- 37 F4.2 mag e_imag DES i magnitude error
39- 43 F5.2 mag zmag DES z magnitude
45- 48 F4.2 mag e_zmag DES z magnitude error
50- 54 F5.2 mag Ymag DES Y magnitude
56- 59 F4.2 mag e_Ymag DES Y magnitude error
61- 65 F5.2 mag Jmag 2MASS J magnitude
67- 70 F4.2 mag e_Jmag 2MASS J magnitude error
72- 76 F5.2 mag Hmag 2MASS H magnitude
78- 81 F4.2 mag e_Hmag ?=- 2MASS H magnitude
83- 87 F5.2 mag Kmag 2MASS K magnitude
89- 92 F4.2 mag e_Kmag ?=- 2MASS K magnitude
94- 98 F5.2 mag W1mag WISE W1 magnitude
100-103 F4.2 mag e_W1mag WISE W1 magnitude error
105-109 F5.2 mag W2mag WISE W2 magnitude
111-114 F4.2 mag e_W2mag WISE W2 magnitude error
--------------------------------------------------------------------------------
Note (1): Notes as follows:
C = Sample only from Reyle (2018A&A...619L...8R 2018A&A...619L...8R, Cat. J/A+A/619/L8), with
Gaia coordinates, i, z, Y photometry from the PS1 and
J, H, K photometry from the 2MASS.
* = for coordinates is the one selected for the spectroscopy observation
instead of 2MASS
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb?.dat tablec?.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Note [C *] Note (1)
4- 5 I2 h RAh Right ascension (J2000)
7- 8 I2 min RAm Right ascension (J2000)
10- 14 F5.2 s RAs Right ascension (J2000)
16 A1 --- DE- Declination sign (J2000)
17- 18 I2 deg DEd Declination (J2000)
20- 21 I2 arcmin DEm Declination (J2000)
23- 26 F4.1 arcsec DEs Declination (J2000)
28- 34 A7 --- SpType Spectral type (2)
36- 40 F5.2 mag imag ?=- DES i magnitude
42- 45 F4.2 mag e_imag ?=- DES i magnitude error
47- 51 F5.2 mag zmag DES z magnitude
53- 56 F4.2 mag e_zmag DES z magnitude error
58- 62 F5.2 mag Ymag DES Y magnitude
64- 67 F4.2 mag e_Ymag DES Y magnitude error
69- 73 F5.2 mag Jmag 2MASS J magnitude
75- 78 F4.2 mag e_Jmag 2MASS J magnitude error
80- 84 F5.2 mag Hmag ?=- 2MASS H magnitude
86- 89 F4.2 mag e_Hmag ?=- 2MASS H magnitude
91- 95 F5.2 mag Kmag ?=- 2MASS K magnitude
97-100 F4.2 mag e_Kmag ?=- 2MASS K magnitude
102-106 F5.2 mag W1mag ?=- WISE W1 magnitude
108-111 F4.2 mag e_W1mag ?=- WISE W1 magnitude error
113-117 F5.2 mag W2mag ?=- WISE W2 magnitude
119-122 F4.2 mag e_W2mag ?=- WISE W2 magnitude error
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Note (1): Notes as follows:
C = Sample and SpT. only from Reyle (2018A&A...619L...8R 2018A&A...619L...8R, Cat. J/A+A/619/L8),
with Gaia coordinates, i, z, Y photometry from the DES and
J, H, K photometry from the 2MASS.
* = for coordinates is the one selected for the spectroscopy observation
instead of DES
Note (2): Spectral type beginning M0.0 as 0.0., L0.0 as 10.0 and T0.0 as 20.0.
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Acknowledgements:
Jerry J.-Y. Zhang [jzhang at iac.es]
History:
From electronic version of the journal
* 03-Sep-2024: Insert into VizieR
* 13-Jan-2025: Table C2 updated; 47 rows were missing
(End) Patricia Vannier [CDS] 05-Aug-2024