Draft version November 1, 2017 Typeset using LATEX twocolumn style in AASTeX61
PARALLAXES OF COOL OBJECTS WITH WISE : FILLING IN FOR GAIA
Christopher A. Theissen1, 2
arXiv:1710.11127v1 [astro-ph.SR] 30 Oct 2017
1 Department 2 Center
of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Dr., Mail Code 0424, La Jolla, CA 92093,
USA
Submitted to ApJ ABSTRACT I use the multi-epoch astrometry from the Wide-field Infrared Survey Explorer (WISE ) to demonstrate a method to measure proper motions and trigonometric parallaxes with precisions of ∼3 mas yr−1 and ∼7 mas, respectively, for low-mass stars and brown dwarfs. This method relies on WISE single exposures (Level 1b frames) and a Markov Chain Monte Carlo method. I discuss the limitations of Gaia in observing low-mass stars and brown dwarfs, and show that WISE will be able to measure astrometry past the limit of Gaia (sources fainter than W 2 ≈ 11). I apply this method to WISE data of 17 nearby (. 17 pc) dwarfs with spectral types between M6.5–Y2 and previously measured trigonometric parallaxes, and show good agreement between this method and literature values. I provide new astrometric measurements for ten additional low-mass dwarfs with spectral types between M6–T5.5 and with estimated photometric distances < 17 pc. Only three of these objects are contained within Gaia Data Release 1. Keywords: techniques: miscellaneous — astrometry — parallaxes — proper motions — brown dwarfs — stars: low-mass
[email protected]
2
Theissen 1. INTRODUCTION
With the imminent release of proper motions and trigonometric parallax measurements for over a billion sources from the Gaia satellite (Perryman et al. 2001), it is important to understand what objects will not be included in the final catalog. Theissen et al. (2017) investigated the Gaia shortfall and found that Gaia will be limited in its ability to observe ultracool dwarfs (spectraltypes later than mid-L) at distances & 10 pc due to its relatively blue bandpass. A number of projects are aimed at measuring trigonometric parallaxes of these ultracool dwarfs (e.g., Dupuy & Liu 2012; Beichman et al. 2013; Faherty et al. 2012; Kirkpatrick et al. 2014; Dupuy et al. 2016; Skinner et al. 2016; Smart et al. 2017b). However, these projects rely on either: 1) numerous epochs of ground-based and space-based observations, using facilities such as the Spitzer Space Telescope (Werner et al. 2004); or 2) survey data spanning multiple epochs, such as the Digitized Sky Survey (DSS), the Wide-field Infrared Survey Explorer (WISE ; Wright et al. 2010), or the Two Micron All-Sky Survey (2MASS; Skrutskie et al. 2006). Here, I outline a method to measure proper motions and trigonometric parallaxes of nearby (.20 pc), ultracool objects using publicly available WISE data. In Section 2, I discuss the properties and limitations of Gaia and WISE. I describe my method for measuring proper motions and parallaxes in Section 3. I make comparisons between my method and previous literature measurements for 17 nearby, low-mass dwarfs in Section 3.1. In Section 3.2, I provide new measurements for ten nearby, ultracool dwarfs. I discuss the utility of my method for the immediate future in Section 4. 2. GAIA AND WISE LIMITATIONS
Gaia is currently conducting the largest astrometric mission to date, with an expected yield of over 1 billion sources with measured proper motions and precise trigonometric parallaxes (.16 µas for low-mass stars with V . 14; Perryman et al. 2001). Theissen et al. (2017) quantified the shortfall of ultracool objects within Gaia Data Release 1 (Gaia Collaboration et al. 2016b,a), using matches between the Late-Type Extension to the Motion Verified Red Stars catalog (LaTE-MoVeRS) and Gaia DR1. They found that Gaia is severely limited in its ability to observe spectral types later than ∼L5 farther than ∼10 pc. I reevaluated the Gaia shortfall using the LaTEMoVeRS sample by comparing the fraction of LaTEMoVeRS sources with a counterpart found within Gaia DR1 as a function of W 2 magnitude (4.6 µm) and Sloan Digital Sky Survey (SDSS; York et al. 2000) i − z color (Figure 1). The fraction of matches typically drops below ∼30% for sources later than ∼L4 with W 2 > 11. This is similar to the fraction of known L and T dwarfs matched to Gaia DR1 in the study of Smart et al. (2017a), ∼ 24% matched; 321 out of 1317 with G < 23.
Figure 1 also shows the total p WISE positional uncertainty for a single frame (i.e., σα2 + σδ2 ) as a function of W 2 magnitude using the original MoVeRS catalog (Theissen et al. 2016). The W 2-absolute magnitude ranges for M, L, and T dwarfs (Filippazzo et al. 2015), and Y dwarfs (Tinney et al. 2014) are indicated with gray shaded regions. The approximate Gaia limiting magnitude is denoted with the red dotted line (W 2 = 11), indicating that WISE can provide astrometric measurements of ultracool objects past the limits of Gaia. 3. PARALLAXES USING WISE MULTI-EPOCH
DATA The all-sky observations made by WISE are ideal for astrometric studies because they span multiple epochs, most separated by ∼ 6 months. The original WISE mission surveyed the entire sky in four bands, 3.4, 4.6, 12, and 22 µm (hereafter W 1, W 2, W 3, and W 4). This original mission lasted from December 2009 to August 2010, after which the cryogen was depleted, and WISE observed in W 1, W 2, and W 3 until September (3-band survey; ∼30% of the sky1 ). WISE continued to observe in W 1 and W 2 as part of the NearEarth Object Wide-field Infrared Survey Explorer (NEOWISE; Mainzer et al. 2011) mission. In December 2013, WISE was reactivated to continue surveying the entire sky in W 1 and W 2 as part of the NEOWISEReactiviation (NEOWISE-R; Mainzer et al. 2014) mission. The NEOWISE-R mission is currently ongoing. The combined WISE dataset contains > 7 epochs for every source, with a cadence of ∼6 months and a time baseline of ∼6.5 years. Each single epoch has 12–13 7.7 second exposures in W 1 and W 22 , and possibly more exposures depending on depth of coverage for a given line-of-sight. The survey strategy of WISE was to observe fields close to 90◦ Solar elongation, which places observed objects close to their maximum parallax factors (Kirkpatrick et al. 2014). Many studies have computed parallaxes using WISE data, combined with either higherpositional precision observations (e.g., Spitzer, Keck), and/or data providing a longer time baseline (e.g., DSS, 2MASS), for nearby objects (e.g., Beichman et al. 2013; Luhman 2013; Kirkpatrick et al. 2014; Scholz 2014). However, the numerous epochs of current WISE data now allow relatively precise (. 10 mas) parallax measurements to be made without the need for further data. An illustration of the parallax method described here is shown in Figure 2 for 2MASS J02550357−4700509, a nearby (∼5 pc) L8 dwarf (Mart´ın et al. 1999; Patten et al. 2006; Kirkpatrick et al. 2008; Faherty et al. 2012). First, all Level 1b (L1b) source catalogs (i.e., All1 2
http://wise2.ipac.caltech.edu/docs/release/3band/ http://wise2.ipac.caltech.edu/docs/release/allsky/
3
Parallaxes with WISE
W2
14
L6
L8 1.0
4
5
2
1
1
6
3
2
2
1
45
14
10
7
101
39
19
13
11
223
77
22
35
11
482
181
69
54
22
932
362
111
87
50
1753 642
244
178
83
2825 1091 416
322
162
16
2
4313 1911 764
510
238
15
1
6017 2626 1061 773
316
26
2
6645 2814 1215 666
213
17 1
3034 1238 393
16
L5
21
10
12
M8 M9 L3 1
166
23
368
167
37
10
3
37
12
5
1
2
1
1
1
1
1
1
1
5
2
1
8
2
10
5
0.8
1 2
1
0.6
1
0.4 1
1
0.2
1
18
0.0
1.0
1.5
2.0
2.5
Fraction of LaTE-MoVeRS Sources with Matches in Gaia DR1
M7 4
3.0
T Dwarfs @ 10 pc
104
103
102
400 200
101
Number of Dwarfs
600
L Dwarfs @ 10 pc
800
Y Dwarfs @ 10 pc
≈ Gaia limit
1000
p
σα2 + σδ2 (mas)
1200
M Dwarfs @ 10 pc
i−z
100
0 10
12
14
16
18
W2 Figure 1. Top: Fraction of matches between the LaTEMoVeRS sample and Gaia DR1 as a function of W 2 and i − z. The number on each bin indicates the total number of LaTE-MoVeRS sources within that bin, and the color of the bin corresponds to the fraction of stars with matches in Gaia DR1 (black colored text indicates a fraction > 0.7). The fraction of Gaia DR1 matches drops below ∼30% for all spectral types later than ∼L4 with W 2 > 11 (area enclosed with red-dotted lines). Approximate spectral types from Schmidt et al. (2015) are listed on the top. Bottom: 2-d histogram of total WISE positional uncertainty (single frames) versus W 2 magnitude for the MoVeRS catalog. Bin areas are 0.1 mag × 5 mas. Also shown are the MW 2 ranges (gray shaded areas) for M, L, and T dwarfs taken from Filippazzo et al. (2015), and the range for Y dwarfs from Tinney et al. (2014). The astrometric precision hits a floor of ∼50 mas for relatively bright sources. Y dwarfs typically have a single-band measurement (W 2), with low signal-to-noise, which will push them to higher positional uncertainties (> 300 mas). The approximate limit for Gaia is indicated by the red dotted line (W 2 = 11).
Sky, 3-band, NEOWISE Post-Cryo, and NEOWISE-R) are queried for objects within 3000 of the expected position of 2MASS J02550357−4700509. L1b source catalogs contain sources extracted from each single exposure3 . Sources were grouped by epoch, demarcated by 6 month periods starting 91 days after the mean modified Julian date (MJD) of the first epoch (shown as dotted lines in the top and middle panels of Figure 2). Next, the uncertainty weighted average position for each epoch is determined using the WISE reported astrometry position values (α, δ, σα , σδ ) and a 3-σ clip to remove outliers. Additionally, the observing epoch time is selected to be the average MJD for each epoch, over a period that may span ∼1–10 days. Uncertainties (σα and σδ ) were computed using the weighted positional uncertainty per epoch, as illustrated in the inset figure of the bottom panel of Figure 2 and given by, 1 hσα,δ i = pP , (1) 2 N 1/σi
where N is the number of frames within the given epoch. The astrometric solution was computed from, (αi − α0 ) cos δ0 = µα (ti − t0 ) + π(Pα,i − Pα,0 ), (δi − δ0 ) = µδ (ti − t0 ) + π(Pδ,i − Pδ,0 ),
(2) (3)
where the subscript 0 denotes the first epoch, and the subscript i denotes each subsequent epoch. Pα,δ represents the parallax factors (van Dekamp 1967) given by (Green 1985), Pα = X sin α − Y cos α,
(4)
Pδ = X cos α sin δ + Y sin α sin δ − Z cos δ,
(5)
where X, Y, Z are the components of the barycentric position vector of the Earth obtained from the JPL DE430 solar system ephemeris. These equations were solved using a Markov Chain Monte Carlo (MCMC) routine built on the emcee code (Foreman-Mackey et al. 2013), assuming normally distributed parameters and uniform priors. 3.1. Comparison to Literature Astrometric Measurements I applied the MCMC routine described in the previous section to 17 known, nearby, low-mass objects with generally well-determined parallaxes (Y2 (Kirkpatrick et al. 2012); W 2 = 14.353 ± 0.045 WISE Beichman et al. (2013)
∼6.5
∼3
...
WISE J085510.83−071442.5; >Y2 (Tinney et al. 2014); W 2 = 14.016 ± 0.048 (Wright et al. 2014) WISE
∼6.5
∼3.7
277.12949
26.84381
...
...
a No uncertainties reported.
∼174 ∼50
1073 ± 41
1069 ± 11
153 ± 13
90 ± 10
∼2.5
∼6.5
∼2.5 ∼7
∼2.5
b Kirkpatrick et al. (2012) quote a value of π = 193 ± 26 mas and cite the measurement to a pre-published version of Marsh et al. (2013).
c Measurements made using only NEOWISE(-R) data.
d Kirkpatrick et al. (2012) quote a value of π = 164 ± 24 mas and cite the measurement to a pre-published version of Marsh et al. (2013).
For 15 of the 17 comparisons, my computed parallax values are within the 1-σ combined uncertainty of the highest precision literature value, and all sources are within the 2-σ combined uncertainty of the literature value. The full astrometric solution for 2MASS J02550357−4700509 is shown in Figure 3. Figure 4 shows the residuals between the parallax value derived using WISE and the highest precision literature parallax, as a function of W 2 magnitude. The astrometric precision severely deteriorates for sources fainter than W 2 ≈ 14, setting the approximate limit for the where this method is valid. The sources beyond 1-σ include 2MASS J2322−3133 and WISEP J1506+7027. 2MASS J2322−3133 is a relatively distant (17.1 ± 1.6 pc), L0 dwarf (Reid et al. 2008; Faherty et al. 2012), indicating the approximate distance limit at this W 2 magnitude. The precision of this method will have a strong dependence on W 2 magnitude, and can be assessed in the future with a larger control sample. The second outlier, WISEP J1506+7027, has a > 2-σ discrepant parallax measurement from the value reported in Marsh et al. (2013). However, WISEP J1506+7027 is an outlier in the Marsh et al. (2013) absolute magnitude–spectral type diagrams (see Marsh et al. 2013 Figures 4 and 5). The distance computed here of 5.2 ± 0.2 pc places WISEP J1506+7027 on the
Kirkpatrick et al. (2012) relationships for MH –spectral type and MW 2 –spectral type (MH = 15.06 ± 0.11; MW 2 = 12.68 ± 0.10). In principle, this method can be applied to any source bright enough to be extracted within a single WISE L1b frame. Saturated photometry may cause an issue with centroiding. Crowded fields also pose a challenge due to multiple objects within each search radius, however, with proper source selection in each epoch’s catalog, any nearby source detected by WISE can have its parallax measured. It is unlikely that robust parallaxes (. 15% uncertainty) can be measured farther than ∼17 pc using WISE alone, assuming an average parallax precision of 9 mas, however, this distance limit is highly dependent on W 2 magnitude. Only the first six objects listed in Table 1 are contained within Gaia DR1, which is roughly consistent with the W 2 6 11 limit discussed in Section 2. The computed parallax values are relative measurements, not absolute, since the positional solution for WISE is derived from both moving and non-moving sources. Without knowing the bulk movement of the calibration objects, absolute measurements cannot be made. Assuming a correction of ∼2 mas from relative to absolute using the modeling results reported in Dupuy & Kraus (2013), any correction will be smaller than the uncertainty in this method, so the reported values are
7
Parallaxes with WISE
WISE J104915.57−531906.1
0 −0.5 ∆α cos δ
−5
∆α (arcsec)
0.0
∆δ
−1.0
−10
0.5
MCMC Fit µα cos δ = −2778 ± 2 mas yr−1 µδ = 360 ± 2 mas yr−1 π = 506 ± 6 mas
−15 −20
55500
56000
56500
0.0 57000
57500
55500
MJD (day)
56000
56500
57000
∆δ (arcsec)
Motion + offset (arcsec)
5
57500
MJD (day)
Figure 3. Left: Astrometric solution for WISE J104915.57−531906.1 (solid lines). The α and δ solutions are offset for visibility. Individual positions for each exposure are shown as translucent gray points, with the blue points and cyan triangles indicating the uncertainty weighted mean positions for each epoch in α and δ, respectively. Errorbars are plotted, but are typically smaller than the plotted symbols. Right: Astrometric solution with the proper motions removed. The dark gray band indicates the uncertainty in the parallax. The complete figure set (17 images) is available below.
500
150 100
0
10
−50
−100 −150 7
8
9
10
11
5 0 12
13
d (pc)
400 15
50
300
πlit. (mas)
20
≈ Gaia limit
πthis study − πlit. (mas)
25
200 100
14
W2 Figure 4. Residuals of parallaxes derived here using WISE data to literature parallax measurements. The symbol color and colorbar indicate the literature value of the parallax. The four points with red circles indicate the measurements from Marsh et al. (2013), and the measurements Kirkpatrick et al. (2012) cite to a pre-published version of Marsh et al. (2013). The blue dashed line shows the approximate distance limit (right y-axis) as a function of W 2 magnitude for 15% uncertainties using this method.
8
Theissen
likely consistent with absolute parallaxes within the uncertainties. 3.2. New and Significantly Improved Astrometric Measurements There are many known low-mass objects estimated to be within 17 pc based on spectro-photometric parallax relationships, that have either no trigonometric parallax measurement (254 within the Winters et al. 2015 southern hemisphere 25 pc sample alone), or measurements with large uncertainties (>20%). Here, I investigate ten such cases, sourced from the literature to cover a range of spectral types, distances, and W 2 magnitudes, three of which are listed in Gaia DR1 (Table 2). In Figure 5, I show the astrometric solution to one of these cases, SDSS J141624.08+134826.7, an unusually blue L6 dwarf with an estimated distance of ∼8 pc (Bowler et al. 2010; Schmidt et al. 2010a; Scholz 2010). The sources in Gaia DR1 should have more precise measurements in the near future. The remainder will require additional astrometric observations to more precisely determine their parallaxes. Using the sources from Tables 1 and 2, I computed a 2nd order polynomial fit to the parallax uncertainties divided by 15% (the approximate parallax limit where 6 15% uncertainties can be achieved) as a function of W 2 magnitude. The fit is shown in Figure 3 as the blue dashed line corresponding the the y-axis on the right. Bright sources (W 2 . 8) can potentially have their parallaxes measured out to distances of ∼25 pc, with sources at the Gaia magnitude limit (W 2 ≈ 11) requiring distances within ∼17 pc. These limits will be validated in the future with a larger control sample. 4. DISCUSSION
The technique presented here has the potential to find new, nearby, ultracool objects, and measure relatively accurate parallaxes without the need for follow-up observations. This is particularly important as Spitzer is expected to be retired in 2018. Its replacement, the James Webb Space Telescope (JWST ; Gardner et al. 2006), while sensitive to these faint dwarfs, is an unlikely facility for a dedicated parallax program. As discussed here and in Theissen et al. (2017); Smart et al. (2017a), Gaia will not provide parallaxes for most of the lowest mass stars and brown dwarfs, leaving only ground-based programs. The WISE method described here is a useful alternative for the nearest (. 17 pc) ultracool objects, and a follow-up paper will report measurements for all ultracool dwarfs estimated to be within this distance. C.A.T would like to give his sincerest thanks to Adam Burgasser, Julie Skinner, Aurora Kesseli, and Andrew West for providing comments which greatly improved this manuscript. C.A.T. would also like to
thank Julie Skinner for helpful discussion leading up to this manuscript. This material is based upon work supported by the National Aeronautics and Space Administration under Grant No. NNX16AF47G issued through the Astrophysics Data Analysis Program. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS web site is www.sdss.org. SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, HarvardSmithsonian Center for Astrophysics, Instituto de Astrof´ısica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU) / University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut f¨ ur Astrophysik Potsdam (AIP), Max-Planck-Institut f¨ ur Astronomie (MPIA Heidelberg), Max-Planck-Institut f¨ ur Astrophysik (MPA Garching), Max-Planck-Institut f¨ ur Extraterrestrische Physik (MPE), National Astronomical Observatories of China, New Mexico State University, New York University, University of Notre Dame, Observat´ario Nacional / MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Aut´onoma de M´exico, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University, and Yale University. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www. cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https:// www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This research made use of Astropy, a communitydeveloped core Python package for Astronomy (Astropy Collaboration et al. 2013). Plots in this publication were made using Matplotlib (Hunter 2007). This research has made use of the SIMBAD database, operated at
9
Parallaxes with WISE
10.0
MCMC Fit µα cos δ = 1959 ± 2 mas yr−1 µδ = −336 ± 2 mas yr−1 π = 190 ± 7 mas
0.0 −0.2 −0.4
7.5
∆α (arcsec)
12.5
5.0 2.5
0.1
∆α cos δ
0.0
0.0 −2.5
∆δ
55500
−0.1 56000
56500
57000
57500
55500
56000
MJD (day)
56500
57000
∆δ (arcsec)
Motion + offset (arcsec)
WISEA J154045.67−510139.3
57500
MJD (day)
Figure 5. Astrometric solution for WISEA J154045.67−510139.3, similar to Figure 3. The complete figure set (10 images) is available below.
Table 2. New and Updated Astrometric Measurements Source
SpT
SpT
W2
Ref. WISEA J154045.67−510139.3
M6
1
2MASS J03140344+1603056
L0
2
2MASS J15065441+1321060
L3
3
SDSS J141624.08+134826.7
L6
4
SDSS J090837.91+503207.5
L8
4
WISE J003110.04+574936.3
L9
5
WISE J203042.79+074934.7
T1.5
6
WISE J185101.83+593508.6
L9
5
PSO J140.2308+45.6487
L9
6
T5.5
6
WISE J223617.59+510551.9
µα cos δ (mas
7.465 ± 0.022
yr−1 )
µδ (mas
yr−1 )
π
πlit.
πlit.
In Gaia
(mas)
(mas)
Ref.
DR1?
190 ± 7
165 ± 41
88 ± 10
83 ± 14
1959 ± 2
−336 ± 2
10.872 ± 0.021
−1086 ± 4
−34 ± 3
11.651 ± 0.023
−438 ± 4
−505 ± 5
12.129 ± 0.024
667 ± 6
−133 ± 6
113 ± 16
92 ± 8
−95 ± 5
−894 ± 6
91 ± 14
70 ± 7
10.649 ± 0.021
11.026 ± 0.020
11.843 ± 0.021
12.178 ± 0.022
12.439 ± 0.023
12.499 ± 0.025
−235 ± 4 69 ± 4
519 ± 4 33 ± 2
715 ± 7
7
Y
69 ± 11
8
N
3
N
105 ± 10
127 ± 27
9
N
4
Y
87 ± 10
91 ± 8
10
N
5
N
91 ± 8
10
Y
5
N
106 ± 9
5
N
−67 ± 3
75 ± 10
104 ± 4
−20 ± 4 438 ± 3
309 ± 8
119 ± 13
63 ± 7
118 ± 18
122 ± 24
Note—(1) Kirkpatrick et al. 2014; (2) Reid et al. 2008; (3) Gizis et al. 2000; (4) Schmidt et al. 2010b; (5) Best et al. 2013; (6) Mace et al. 2013; (7) Kirkpatrick et al. 2014; (8) Reid et al. 2006; (9) Scholz 2010; (10) Thompson et al. 2013.
CDS, Strasbourg, France. This research has made use of NASA’s Astrophysics Data System. This research has
also made use of the VizieR catalogue access tool, CDS, Strasbourg, France (Wenger et al. 2000).
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11
York, D. G., Adelman, J., Anderson, Jr., J. E., et al. 2000, AJ, 120, 1579
12
Theissen
WISE J104915.57−531906.1
0 −0.5 −5
∆α cos δ
−1.0
−10 −15 −20
∆α (arcsec)
0.0
∆δ
0.5
MCMC Fit µα cos δ = −2778 ± 2 mas yr−1 µδ = 360 ± 2 mas yr−1 π = 506 ± 6 mas 55500
56000
56500
∆δ (arcsec)
Motion + offset (arcsec)
5
0.0 57000
57500
55500
56000
MJD (day)
56500
57000
57500
MJD (day)
0.50
0 0.25 ∆α cos δ
−2
0.00
−4 −6
0.0
MCMC Fit µα cos δ = −1199 ± 2 mas yr−1 µδ = −989 ± 2 mas yr−1 π = 243 ± 6 mas 55500
56000
56500
−0.2 57000
57500
55500
56000
MJD (day)
56500
57000
∆δ (arcsec)
Motion + offset (arcsec)
∆δ
∆α (arcsec)
2MASS J10481463−3956062
57500
MJD (day)
0.2
0 0.0
∆δ
−2
−0.2
−4 −6 −8
0.2 MCMC Fit µα cos δ = −909 ± 2 mas yr−1 µδ = −1166 ± 3 mas yr−1 π = 116 ± 7 mas 55500
56000
56500
MJD (day)
0.0
57000
57500
55500
56000
56500
MJD (day)
57000
57500
∆δ (arcsec)
Motion + offset (arcsec)
∆α cos δ
∆α (arcsec)
2MASS J00113182+5908400
13
Parallaxes with WISE
4 2
MCMC Fit µα cos δ = 935 ± 3 mas yr−1 µδ = −493 ± 3 mas yr−1 π = 76 ± 8 mas
0.0 −0.2 −0.4
∆α cos δ
0.1 0 −2
0.0 ∆δ
−0.1 55500
∆α (arcsec)
6
56000
56500
57000
57500
55500
56000
MJD (day)
56500
57000
57500
∆δ (arcsec)
Motion + offset (arcsec)
2MASS J23062928−0502285
−0.2
MJD (day)
2MASS J02550357−4700509
4 2
0.0 −0.2 −0.4
∆α cos δ
0.25
0 −2 −4
∆α (arcsec)
6
0.00 ∆δ
55500
−0.25 56000
56500
57000
57500
55500
56000
MJD (day)
56500
57000
57500
∆δ (arcsec)
Motion + offset (arcsec)
0.2 MCMC Fit µα cos δ = 1043 ± 3 mas yr−1 µδ = −552 ± 3 mas yr−1 π = 203 ± 7 mas
−0.50
MJD (day)
6
MCMC Fit µα cos δ = −155 ± 2 mas yr−1 µδ = 1130 ± 3 mas yr−1 π = 209 ± 9 mas
0.5
0.0
4 2
0.2
∆δ
0.0 −0.2
0 ∆α cos δ
55500
−0.4 56000
56500
MJD (day)
57000
57500
55500
56000
56500
MJD (day)
57000
57500
∆δ (arcsec)
Motion + offset (arcsec)
8
∆α (arcsec)
2MASS J08173001−6155158
14
Theissen
5.0 2.5
MCMC Fit µα cos δ = −1196 ± 2 mas yr−1 µδ = 1040 ± 3 mas yr−1 π = 192 ± 8 mas
0.2 0.0
∆δ
−0.2
0.0 −2.5
0.25 ∆α cos δ
0.00
−5.0
−0.25
−7.5
−0.50 55500
56000
56500
57000
57500
55500
56000
MJD (day)
56500
57000
∆δ (arcsec)
Motion + offset (arcsec)
7.5
∆α (arcsec)
WISEP J150649.97+702736.0
57500
MJD (day)
0.2 1
∆α cos δ
0.0 0 ∆δ
0.2
−1 −2 −3
MCMC Fit µα cos δ = 166 ± 3 mas yr−1 µδ = −416 ± 4 mas yr−1 π = 71 ± 9 mas 55500
56000
0.0
56500
57000
57500
55500
56000
MJD (day)
56500
57000
∆δ (arcsec)
Motion + offset (arcsec)
2
∆α (arcsec)
2MASS J04455387-3048204
57500
MJD (day)
2
0.5 ∆α cos δ
0.0 0
∆α (arcsec)
4
∆δ
−2 −4 −6
0.0
MCMC Fit µα cos δ = 528 ± 7 mas yr−1 µδ = −1034 ± 7 mas yr−1 π = 192 ± 20 mas 55500
56000
56500
−0.5 57000
MJD (day)
57500
55500
56000
56500
57000
MJD (day)
57500
∆δ (arcsec)
Motion + offset (arcsec)
2MASS J09393548−2448279
15
Parallaxes with WISE
Motion + offset (arcsec)
0
0.0 ∆δ
−0.2
−1 −2 −3 −4
0.2 MCMC Fit µα cos δ = −176 ± 4 mas yr−1 µδ = −564 ± 4 mas yr−1 π = 74 ± 11 mas 55500
56000
56500
0.0 −0.2 57000
57500
55500
56000
MJD (day)
56500
57000
∆δ (arcsec)
0.2
∆α cos δ
∆α (arcsec)
2MASS J23224684-3133231
57500
MJD (day)
0.5
∆δ
0.0 0 −2 −4 −6
0.4
∆α cos δ
0.2
MCMC Fit µα cos δ = −912 ± 10 mas yr−1 µδ = 358 ± 12 mas yr−1 π = 251 ± 31 mas 55500
∆α (arcsec)
2
56000
56500
0.0 −0.2 57000
57500
55500
56000
MJD (day)
56500
57000
∆δ (arcsec)
Motion + offset (arcsec)
UGPS J072227.51−054031.2
57500
MJD (day)
0.5 0.0 −0.5
10
0.5 5
∆α cos δ
0.0 0
∆α (arcsec)
15
MCMC Fit µα cos δ = 2619 ± 17 mas yr−1 µδ = 184 ± 17 mas yr−1 π = 138 ± 42 mas
−0.5
∆δ
55500
56000
56500
MJD (day)
57000
57500
55500
56000
56500
MJD (day)
57000
57500
∆δ (arcsec)
Motion + offset (arcsec)
WISEA J025409.55+022358.5
16
Theissen
10.0 7.5
MCMC Fit µα cos δ = −584 ± 11 mas yr−1 µδ = 1667 ± 13 mas yr−1 π = 116 ± 29 mas
0.5 0.0
5.0 2.5
−0.5 0.5 ∆δ
0.0
0.0 −2.5
∆α cos δ
−0.5 55500
56000
56500
57000
57500
55500
56000
MJD (day)
56500
57000
∆δ (arcsec)
Motion + offset (arcsec)
12.5
∆α (arcsec)
2MASS J07290002−3954043
57500
MJD (day)
2MASS J22282889−4310262
1
0.0 −0.5
0 ∆δ
−1
0.5 MCMC Fit µα cos δ = 148 ± 17 mas yr−1 µδ = −371 ± 21 mas yr−1 π = 104 ± 47 mas
−2 −3
55500
56000
56500
0.0 −0.5 57000
57500
55500
56000
MJD (day)
56500
57000
57500
∆δ (arcsec)
Motion + offset (arcsec)
0.5 ∆α cos δ
∆α (arcsec)
1.0 2
−1.0
MJD (day)
2
∆δ
0
0 −5
∆α cos δ
−2 2
−10 −15 −20
MCMC Fit µα cos δ = −8151 ± 76 mas yr−1 µδ = 678 ± 76 mas yr−1 π = 468 ± 72 mas 56800
57000
57200
57400
MJD (day)
0 −2 57600
56800
57000
57200
57400
MJD (day)
57600
∆δ (arcsec)
Motion + offset (arcsec)
5
∆α (arcsec)
WISE J085510.83−071442.5
17
Parallaxes with WISE
WISEP J041022.71+150248.5 ∆α cos δ
0
0
−2
∆δ
−5 −10 −15
2 MCMC Fit µα cos δ = 981 ± 46 mas yr−1 µδ = −2261 ± 52 mas yr−1 π = 202 ± 116 mas 55500
56000
0
56500
57000
57500
55500
56000
MJD (day)
56500
57000
∆δ (arcsec)
Motion + offset (arcsec)
5
∆α (arcsec)
2
10
57500
MJD (day)
8
MCMC Fit µα cos δ = 1073 ± 41 mas yr−1 µδ = 186 ± 49 mas yr−1 π = 169 ± 96 mas
2 0
6
−2
∆α cos δ
2
4 2
0
0 −2
∆δ
−2
55500
∆α (arcsec)
10
56000
56500
57000
57500
55500
56000
MJD (day)
56500
57000
∆δ (arcsec)
Motion + offset (arcsec)
WISEPA J182831.08+265037.8
57500
MJD (day)
10.0
MCMC Fit µα cos δ = 1959 ± 2 mas yr−1 µδ = −336 ± 2 mas yr−1 π = 190 ± 7 mas
0.0 −0.2 −0.4
7.5
∆α (arcsec)
12.5
5.0 2.5
0.1
∆α cos δ
0.0
0.0 −2.5
∆δ
55500
−0.1 56000
56500
MJD (day)
57000
57500
55500
56000
56500
MJD (day)
57000
57500
∆δ (arcsec)
Motion + offset (arcsec)
WISEA J154045.67−510139.3
18
Theissen
0.2
0.0
0.0 ∆α cos δ
−0.5 −1.0 −1.5
0.2 MCMC Fit µα cos δ = −235 ± 4 mas yr−1 µδ = −67 ± 2 mas yr−1 π = 75 ± 10 mas 55500
56000
0.0
56500
57000
57500
55500
56000
MJD (day)
56500
57000
∆δ (arcsec)
Motion + offset (arcsec)
∆δ
0.5
∆α (arcsec)
2MASS J03140344+1603056
57500
MJD (day)
0.2
0
−2
0.0 −0.2
∆α cos δ
0.4
−4 −6
0.2
MCMC Fit µα cos δ = −1086 ± 4 mas yr−1 µδ = −34 ± 3 mas yr−1 π = 88 ± 10 mas 55500
56000
56500
0.0
57000
57500
55500
56000
MJD (day)
56500
57000
57500
∆δ (arcsec)
Motion + offset (arcsec)
∆δ
∆α (arcsec)
2MASS J15065441+1321060
−0.2
MJD (day)
1.00 0.75
0.2
MCMC Fit µα cos δ = 69 ± 4 mas yr−1 µδ = 104 ± 4 mas yr−1 π = 105 ± 10 mas
0.0 −0.2
∆δ
−0.4 0.2
0.50 0.25
0.0 0.00 −0.25
∆α (arcsec)
1.25
−0.2
∆α cos δ
55500
56000
56500
MJD (day)
57000
57500
55500
56000
56500
MJD (day)
57000
57500
∆δ (arcsec)
Motion + offset (arcsec)
SDSS J141624.08+134826.7
19
Parallaxes with WISE
SDSS J090837.91+503207.5
0.2
0 ∆δ
0.0
−1 −2 −3
∆α (arcsec)
0.4
−0.2 0.1 MCMC Fit µα cos δ = −438 ± 4 mas yr−1 µδ = −505 ± 5 mas yr−1 π = 119 ± 13 mas 55500
56000
56500
0.0 −0.1 57000
57500
55500
56000
MJD (day)
56500
57000
57500
∆δ (arcsec)
Motion + offset (arcsec)
∆α cos δ
−0.2
MJD (day)
MCMC Fit µα cos δ = 519 ± 4 mas yr−1 µδ = −20 ± 4 mas yr−1 π = 87 ± 10 mas
3
0.2 0.0
2 0.2
∆α cos δ
1 0.0 0
∆δ
55500
56000
56500
57000
57500
55500
56000
MJD (day)
56500
57000
57500
∆δ (arcsec)
Motion + offset (arcsec)
4
∆α (arcsec)
WISE J003110.04+574936.3
−0.2
MJD (day)
3
MCMC Fit µα cos δ = 667 ± 6 mas yr−1 µδ = −133 ± 6 mas yr−1 π = 113 ± 16 mas
0.0 −0.2 −0.4
2
0.2
∆α cos δ
1 0.0 0 ∆δ
−0.2
−1 55500
56000
56500
MJD (day)
57000
57500
55500
56000
56500
MJD (day)
57000
57500
−0.4
∆δ (arcsec)
Motion + offset (arcsec)
4
∆α (arcsec)
WISE J203042.79+074934.7 5
20
Theissen
0.2 0.0 −0.2
2
∆α (arcsec)
MCMC Fit µα cos δ = 33 ± 2 mas yr−1 µδ = 438 ± 3 mas yr−1 π = 63 ± 7 mas
3
−0.4 0.2
1
∆δ
0.0 0
−0.2
∆α cos δ
55500
56000
56500
57000
57500
55500
56000
56500
MJD (day)
57000
∆δ (arcsec)
Motion + offset (arcsec)
WISE J185101.83+593508.6
57500
MJD (day)
0.2
−1
∆δ
0.0
−2
−0.2
−3 −4 −5 −6
0.2 MCMC Fit µα cos δ = −95 ± 5 mas yr−1 µδ = −894 ± 6 mas yr−1 π = 91 ± 14 mas 55500
56000
0.0 −0.2
56500
57000
57500
55500
56000
MJD (day)
56500
57000
∆δ (arcsec)
Motion + offset (arcsec)
∆α cos δ
0
∆α (arcsec)
PSO J140.2308+45.6487 1
57500
MJD (day)
4
0.5
MCMC Fit µα cos δ = 715 ± 7 mas yr−1 µδ = 309 ± 8 mas yr−1 π = 118 ± 18 mas
0.0 −0.5
3 2 ∆α cos δ
1
0.0
0 ∆δ
55500
56000
56500
MJD (day)
57000
57500
55500
56000
56500
MJD (day)
57000
57500
−0.5
∆δ (arcsec)
Motion + offset (arcsec)
5
∆α (arcsec)
WISE J223617.59+510551.9
