J/AJ/150/175 YSOVAR: infrared photometry in NGC 1333 (Rebull+, 2015)
YSOVAR: mid-infrared variability in NGC 1333.
Rebull L.M., Stauffer J.R., Cody A.M., Gunther H.M., Hillenbrand L.A.,
Poppenhaeger K., Wolk S.J., Hora J., Hernandez J., Bayo A., Covey K.,
Forbrich J., Gutermuth R., Morales-Calderon M., Plavchan P., Song I.,
Bouy H., Terebey S., Cuillandre J.C., Allen L.E.
<Astron. J., 150, 175 (2015)>
=2015AJ....150..175R 2015AJ....150..175R (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Stars, variable ; Photometry, infrared
Keywords: circumstellar matter - stars: pre-main sequence - stars: protostars -
stars: variables: general
Abstract:
As part of the Young Stellar Object VARiability (YSOVAR) program, we
monitored NGC 1333 for ∼35 days at 3.6 and 4.5µm using the Spitzer
Space Telescope. We report here on the mid-infrared variability of the
point sources in the ∼10'x∼20' area centered on 03:29:06, +31:19:30
(J2000). Out of 701 light curves in either channel, we find 78
variables over the YSOVAR campaign. About half of the members are
variable. The variable fraction for the most embedded spectral energy
distributions (SEDs) (Class I, flat) is higher than that for less
embedded SEDs (Class II), which is in turn higher than the star-like
SEDs (Class III). A few objects have amplitudes (10-90th percentile
brightness) in [3.6] or [4.5]>0.2mag; a more typical amplitude is
0.1-0.15mag. The largest color change is >0.2mag. There are 24
periodic objects, with 40% of them being flat SED class. This may mean
that the periodic signal is primarily from the disk, not the
photosphere, in those cases. We find 9 variables likely to be
"dippers", where texture in the disk occults the central star, and
11 likely to be "bursters", where accretion instabilities create
brightness bursts. There are 39 objects that have significant trends
in [3.6]-[4.5] color over the campaign, about evenly divided between
redder-when-fainter (consistent with extinction variations) and
bluer-when-fainter. About a third of the 17 Class 0 and/or jet-driving
sources from the literature are variable over the YSOVAR campaign, and
a larger fraction (∼half) are variable between the YSOVAR campaign and
the cryogenic-era Spitzer observations (6-7 years), perhaps because it
takes time for the envelope to respond to changes in the central
source. The NGC 1333 brown dwarfs do not stand out from the stellar
light curves in any way except there is a much larger fraction of
periodic objects (∼60% of variable brown dwarfs are periodic, compared
to ∼30% of the variables overall).
Description:
We present the Young Stellar Object VARiability (YSOVAR) data for
NGC1333. There are 701 objects (see Table1) with mid-infrared light
curves in one or both warm Spitzer bands. All YSOVAR Spitzer light
curve tabular data are available via the YSOVAR data delivery to the
Infrared Science Archive (IRSA;
http://irsa.ipac.caltech.edu/frontpage/). The sky observed by the two
IRAC channels (3.6 and 4.5µm, or IRAC-1 and -2) fields of view is
slightly offset with the central ∼10'*10' region, centered on
03:29:06+31:19:30, covered by both channels. The observations were
obtained under program ID61026, between 2011 October 10 and November
14 (∼35 days).
Near-infrared observations were obtained using the Peters Automated
Infrared Imaging Telescope (PAIRITEL), which is an automated 1.3m
telescope. PAIRITEL was located at the Whipple Observatory at Mt.
Hopkins, Arizona; the same telescope and camera used for the northern
part of 2MASS, PAIRITEL acquired simultaneous J, H, and Ks images.
The observations of NGC1333 were obtained over 24 epochs from 2010
October 7 to 2012 November 19.
We compiled additional photometry from several different sources.
Early in the Spitzer mission, NGC1333 was observed by both the
guaranteed time observations (GTOs) and the Cores-to-Disks (c2d)
Legacy program (Evans et al. 2009, cat. J/ApJS/181/321), with both
IRAC and the Multiband Imaging Photometer for Spitzer (MIPS).
NGC1333 was covered in the Two-Micron All Sky Survey (2MASS; see cat
II/246) and was also located in a field targeted by the long exposure
6X 2MASS program (see cat II/281). As described in Rebull 2015 (cat.
J/AJ/150/17), we included these main 2MASS catalog and deeper 6X
catalog near-infrared JHKs data into our database. We also include
the ∼30 deep JH space-based measurements from Greissl et al.
(2007AJ....133.1321G 2007AJ....133.1321G).
Chandra X-ray Observatory Advanced CCD Imaging Spectrometer for
wide-field imaging (ACIS-I) observations of NGC1333 were first
reported in Getman et al. 2002 (cat. J/ApJ/575/354) and then Winston
et al. 2010 (cat. J/AJ/140/266). There are three pointings in NGC1333,
with obsids 642, 6436, and 6437, with a total exposure time of
119.3ks.
NGC1333 was observed in several optical bands from Subaru and the
Canada-France-Hawaii Telescope (CFHT), and we obtained these data from
the public archives. Optical data from both telescopes cover the full
extent of the region monitored for YSOVAR. NGC1333 was observed in the
i' and z' bands with the Suprime-Cam wide-field camera on Subaru on
2006 November 18. A total of 1 short exposure (10s) and 60 dithered
long exposures (60s) were obtained in each filter as part of the SONYC
project (Scholz et al. 2012, cat. J/ApJ/744/6). NGC1333 was observed
in the ugri filters at several epochs (2005 Sep 27 with g filter; 2008
Dec 21, 2009 Mar 24, 2009 Mar 26, and 2009 Sep 21 with i filter; 2005
Sep 27 with r filter; 2005 Sep 27, 2005 Dec 23, and 2006 Feb 28 with u
filter) with the MegaCam wide-field camera mounted on the CFHT as part
of the DANCE survey (Bouy et al. 2013A&A...554A.101B 2013A&A...554A.101B). The individual
CFHT images were retrieved from the public archives maintained at the
Canadian Astronomy Data Centre.
Single-valued measurements (such as the single-epoch optical
photometry) or metrics (such as the SED slope and class, or mean from
the light curve, etc.) for all of the objects with light curves are
collected in Table1.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 550 701 Contents of single-value object catalog
table5.dat 202 9 Large-amplitude variables
table6.dat 201 17 Class 0 and jet drivers
table7.dat 327 28 Famous Young Stellar Objects (YSOs)
--------------------------------------------------------------------------------
See also:
J/ApJ/799/136 : IN-SYNC. II. Candidate young stars in NGC 1333 (Foster+, 2015)
J/AJ/150/118 : YSOVAR infrared photometry in IRAS 20050+2720
(Poppenhaeger+, 2015)
J/AJ/150/17 : A catalog of point sources toward NGC 1333 (Rebull, 2015)
J/AJ/148/122 : YSOVAR: infrared photometry in Lynds 1688 (Gunther+, 2014)
J/AJ/147/82 : Monitoring of disk-bearing stars in NGC 2264 (Cody+, 2014)
J/ApJ/774/22 : CO observations of YSOs in NGC 1333 (Plunkett+, 2013)
J/ApJ/744/6 : SONYC census of very low-mass objects in NGC1333
(Scholz+, 2012)
J/AJ/140/266 : NGC 1333 X-ray luminous YSOs properties (Winston+, 2010)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/ApJ/674/336 : Spitzer observations of NGC 1333 (Gutermuth+, 2008)
J/AJ/127/1131 : NGC 1333 low-mass stars infrared photometry (Wilking+, 2004)
J/ApJ/575/354 : Young stellar objects in the NGC 1333 (Getman+, 2002)
J/A+AS/106/165 : Near-IR imaging photometry of NGC 1333 (Aspin+ 1994)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- SSTYSV Designation within the Spitzer Space Telescope
(SST) Young Stellar Object VARiability
(YSOVAR) program (HHMMSS.ss+DDMMSS.s; J2000)
(cat)
20- 29 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000) (RA)
31- 40 F10.6 deg DEdeg Declination in decimal degrees (J2000) (Dec)
42- 46 F5.2 mag umag [11.8/23.6]? CFHT/Megacam u-band AB magnitude
(CFHT=Canada-France-Hawaii Telescope)
(cfht_umag)
48- 52 F5.2 mag e_umag [0.01/0.13]? Error in umag (ecfhtumag)
54- 58 F5.2 mag gmag [10.78/24.13]? CFHT/Megacam g-band AB magnitude
(cfht_gmag)
60- 64 F5.2 mag e_gmag [0.01/0.16]? Error in gmag (ecfhtgmag)
66- 70 F5.2 mag rmag [10.66/24.1]? CFHT/Megacam r-band AB magnitude
(cfht_rmag)
72- 76 F5.2 mag e_rmag [0.01/0.17]? Error in rmag (ecfhtrmag)
78- 82 F5.2 mag imag [14.42/25.65]? CFHT/Megacam i-band AB magnitude
(cfht_imag)
84- 88 F5.2 mag e_imag [0.01/0.22]? Error in imag (ecfhtimag)
90- 94 F5.2 mag i'mag [14.26/25.6]? Subaru/Suprime i'-band AB
magnitude (subaru_imag)
96-100 F5.2 mag e_i'mag [0.01/0.11]? Error in i'mag (esubaruimag)
102-106 F5.2 mag z'mag [13.89/25.57]? Subaru/Suprime z'-band AB
magnitude (subaru_zmag)
108-112 F5.2 mag e_z'mag [0.02/0.17]? Error on z'mag (esubaruzmag)
114 A1 --- l_Jmag [>] Lower limit flag on Jmag (l_J)
117-121 F5.2 mag Jmag [8.1/21]? J band magnitude (J) (1)
123-127 F5.2 mag e_Jmag [0.01/0.91]? Uncertainty in Jmag (e_J)
129 A1 --- l_Hmag [>] lower limit flag on Hmag (l_H)
132-136 F5.2 mag Hmag [7.8/20.1]? H band magnitude (H) (1)
138-142 F5.2 mag e_Hmag [0.01/0.6]? Uncertainty in Hmag (e_H)
144 A1 --- l_Ksmag [>] Lower limit flag on Ksmag (l_Ks)
147-151 F5.2 mag Ksmag [7.17/18.62]? Ks band magnitude (Ks) (1)
153-157 F5.2 mag e_Ksmag [0.01/0.6]? Uncertainty in Ksmag (e_Ks)
159 A1 --- l_[3.6] [>] Lower limit flag on [3.6]
162-166 F5.2 mag [3.6] [6.7/18.81]? Spitzer/IRAC 3.6µm band
magnitude (1)
168-172 F5.2 mag e_[3.6] [0.01/0.36]? Uncertainty in [3.6]
174 A1 --- l_[4.5] [>] Lower limit flag on [4.5]
177-181 F5.2 mag [4.5] [5.54/17.35]? Spitzer/IRAC 4.5µm band
magnitude (1)
183-187 F5.2 mag e_[4.5] [0.01/0.6]? Uncertainty in [4.5]
189 A1 --- l_[5.8] [>] Lower limit flag on [5.8]
192-196 F5.2 mag [5.8] [4.58/19.31]? Spitzer/IRAC 5.8µm band
magnitude (1)
198-202 F5.2 mag e_[5.8] [0.01/0.6]? Uncertainty in [5.8]
204 A1 --- l_[8.0] [>] Lower limit flag on [8.0]
207-211 F5.2 mag [8.0] [3/22.2]? Spitzer/IRAC 8.0µm band
magnitude (1)
213-217 F5.2 mag e_[8.0] [0.01/0.81]? Uncertainty in [8.0]
219 A1 --- l_[24] [>] Lower limit flag on [24]
222-226 F5.2 mag [24] [-0.6/18]? Spitzer/MIPS 24µm band
magnitude (1)
228-232 F5.2 mag e_[24] [0.01/0.6]? Uncertainty in [24]
234 A1 --- l_[70] Limit flag on [70]
237-241 F5.2 mag [70] [-3.7/1.1]? Spitzer/MIPS 70µm band
magnitude (1)
243-247 F5.2 mag e_[70] [0.1/0.13]? Uncertainty in [70]
249-253 F5.2 [mW/m2] logFX [-7.1/-3.9]? Log X-ray flux (in erg/s/cm2)
(logfx)
255-259 F5.2 [mW/m2] e_logFX [0.01/0.42]? Error in logFX (logfxerr)
263-267 F5.2 [10-7W] logLX [27.9/30.8]? Log X-ray luminosity (in erg/s)
(loglx)
269-279 A11 --- SpT Spectral type (SpTy)
281-290 A10 --- r_SpT Literature origin of SpT (SpTySrc) (2)
293-296 I4 K Teff [1900/7000]? Effective temperature from Foster
et al. 2015 (cat. J/ApJ/799/136)
298-302 F5.2 --- alpha [-4.41/5.83]? SED slope from 2 to 24µm (see
Section 4.4) (oursedslope24) (3)
304-307 A4 --- Cl SED class from 2 to 24µm (I, II, III, or
flat) (oursedclass24) (4)
309 I1 --- YSOl [0/1]?=0 Is this a literature YSO?
(1=yes, null=no) (YSOlit)
311 I1 --- YSOs [0/1]?=0 Is this a part of standard YSOs set?
(1=yes, null=no); see Section 4.5 for details
(YSOstd)
313 I1 --- YSOx [0/1]?=0 Was this selected for standard set of
YSOs based on X-rays? (1=yes, null=no); see
Section 4.5 for details
315 I1 --- YSOa [0/1]?=0 Is this a part of augmented set of
YSOs? (1=yes, null=no); see Section 4.6 for
details (YSOaug)
317 I1 --- CY [0/1]?=0 Is this Cryo-to-YSOVAR (CY) variable?
(1=yes, null=no); see Section 4.3 for details
(CYvar)
319 I1 --- Var [0/1]?=0 Is this variable over the YSOVAR
campaign? (1=yes, null=no); see Section 4.2
321 I1 --- Mm [0/1]?=0 Is this a newly identified member
based on variability? (1=yes, null=no)
(VarMem) (5)
323-325 I3 --- N3.6 [0/73]? Number of points in 3.6µm band for
YSOVAR campaign (Npts_i1)
327-331 F5.2 mag <[3.6]> [6.66/16.6]? Mean 3.6µm band magnitude
(Mean_i1)
333-337 F5.2 mag med3.6 [6.66/16.64]? Median 3.6µm band magnitude
(Median_i1)
339-343 F5.2 mag s3.6 [0.01/0.3]? Standard 3.6µm band deviation
(Sdev_i1)
345-349 F5.2 mag M3.6 [6.69/16.8]? Maximium 3.6µm band magnitude
(Max_i1)
351-355 F5.2 mag m3.6 [6.64/16.5]? Minimum 3.6µm band magnitude
(Min_i1)
357-361 F5.2 d L3.6 [2.96/33.47]? Length of 3.6µm band light
curve (RangeJDi1)
363-367 F5.2 mag A3.6 [0.02/0.74]? Amplitude of 3.6µm band light
curve (Ampl1090_i1) (6)
369-374 F6.2 --- chi3.6 [0.03/567.5]? The χ2 for 3.6µm band
(Chisq_i1) (7)
376-380 F5.2 d t3.6 [1/22]? Timescale for 3.6µm band
(Timescale_i1)
382-386 F5.2 d P3.6 [1.4/13.4]? Period for 3.6µm band, if
applicable (Period_i1)
388-392 F5.2 --- Mm1 [-1.14/0.52]? M metric for 3.6µm band
(M_i1) (8)
394-398 F5.2 --- Ms1 [-0.9/0.3]? M metric for smoothed 3.6µm
band (Ms_i1) (8)
400-404 F5.2 --- Qm1 [-3.75/4.76]? Q metric for 3.6µm band
(Q_i1) (8)
406-411 F6.2 --- Ql1 [-14.71/40.31]? Q metric for
long-term-trend-subtracted 3.6µm band
(Qlt_i1) (8)
413-415 I3 --- N4.5 [0/73]? Number of points in 4.5µm band for
YSOVAR campaign (Npts_i2)
417-421 F5.2 mag <[4.5]> [6.47/16.33]? Mean 4.5µm band magnitude
(Mean_i2)
423-427 F5.2 mag med4.5 [6.47/16.31]? Median 4.5µm band magnitude
(Median_i2)
429-433 F5.2 mag s4.5 [0.01/0.21]? Standard 4.5µm band deviation
(Sdev_i2)
435-439 F5.2 mag M4.5 [6.49/16.51]? Maximium 4.5µm band magnitude
(Max_i2)
441-445 F5.2 mag m4.5 [6.45/16.2]? Minimum 4.5µm band magnitude
(Min_i2)
447-451 F5.2 d L4.5 [1.54/33.5]? Length of 4.5µm band light
curve (RangeJDi2)
453-457 F5.2 mag A4.5 [0.01/0.51]? Amplitude of 4.5µm band light
curve (Ampl1090_i2) (6)
459-464 F6.2 --- chi4.5 [0.02/633.3]? The χ2 for 4.5µm band
(Chisq_i2) (7)
466-470 F5.2 d t4.5 [0.95/22]? Timescale for 4.5µm band
(Timescale_i2)
472-476 F5.2 d P4.5 [1.4/13.9]? Period for 4.5µm band, if
applicable (Period_i2)
478-482 F5.2 --- Mm2 [-1.4/0.7]? M metric for 4.5µm band
(M_i2) (8)
484-488 F5.2 --- Ms2 [-0.7/0.3]? M metric for smoothed 4.5µm
band (Ms_i2) (8)
490-494 F5.2 --- Qm2 [-4.6/5.8]? Q metric for 4.5µm band
(Q_i2) (8)
496-502 F7.2 --- Ql2 [-161.9/83.9]? Q metric for
long-term-trend-subtracted 4.5µm band
(Qlt_i2) (8)
504-508 F5.2 mag [0/2.45]? Mean 3.6-4.5µm band color index
(Mean_i1i2)
510-514 F5.2 mag sCI [0.01/0.2]? Standard 3.6-4.5µm band color
index deviation (Sdev_i1i2)
516-520 F5.2 d PCI [5.5/9.8]? Period for 3.6-4.5µm band color
index, if applicable (Period_i1i2)
522-526 F5.2 --- Stet [0/0.7]? Stetson index for 3.6, 4.5µm bands
(Stetson_i1i2) (9)
528-532 F5.2 --- C3.6 [-0.52/0.97]? Correlation coefficient for 3.6
vs. 3.6-4.5µm band color color-magnitude
diagram (Correl_i1i1i2)
534-538 F5.2 --- Prob1 [0/0.74]? Probability that correlation is real
in 3.6 vs. 3.6-4.5µm band color CMD
(CorrelProb_i1i1i2)
540-544 F5.2 --- C4.5 [-0.97/0.82]? Correlation coefficient for 4.5
vs. 3.6-4.5µm band color CMD
(Correl_i2i1i2)
546-550 F5.2 --- Prob2 [0/0.7]? Probability that correlation is real
in 4.5 vs. 3.6-4.5µm band color CMD
(CorrelProb_i2i1i2)
--------------------------------------------------------------------------------
Note (1): The JHK and cryo-era Spitzer data (as well as the SED slopes and
classes) are reported in Rebull 2015 (cat. J/AJ/150/17), but are repeated
here for convenience.
Note (2): Reference codes are defined as follows:
Winston10 = Winston et al. 2010 (cat. J/AJ/140/266);
ASR = Aspin et al. 1994 (cat. J/A+AS/106/165);
Scholz12 = Scholz et al. 2012 (cat. J/ApJ/744/6);
Itoh10 = Itoh et al. 2010PASJ...62.1149I 2010PASJ...62.1149I;
Greissl07 = Greissl et al. 2007AJ....133.1321G 2007AJ....133.1321G;
Aspin03 = Aspin (2003AJ....125.1480A 2003AJ....125.1480A);
Wilking04 = Wilking et al. 2004 (cat. J/AJ/127/1131).
Note (3): We define the near-to-mid-infrared (2 to 24µm) slope of the SED as:
α=dlogλFλ/dlogλ.
Note (4): The SED classification scheme is defined in Section 4.4 as:
I = Class I object (α>0.3);
II = Class II object (-1.6<α< -0.3);
III = Class III object (α< -1.6).
flat = Flat-spectrum source (-0.3<α<0.3)
Note (5): The five newly identified candidate members do not stand out in
properties; they have comparable ranges of brightness, light curve shapes,
etc., to the set of more established members. However, as with a
significant fraction of the sample, spectroscopy is required to establish
membership. See Section 4.6 for additional details.
Note (6): We define light curve amplitude over the YSOVAR campaign to be the
difference between the 10th and 90th percentile in the distribution of
points. See Section 6.1 for additional details.
Note (7): For the objects where only one band of data ([3.6] or [4.5]) exists at
all (or where one band may be corrupted by instrumental effects), we can
identify variables from the chi-squared test (χ2), which, for a given
band, is given by Equation (2) in the paper (see Section 4.2).
Note (8): As per Cody et al. 2014 (cat. J/AJ/147/82):
- "The M metric, in combination with timescale and the periodicity measure,
Q, enables us to quantitatively retrieve the morphology classes that were
first established by eye and that presumably represent different
variability mechanisms";
- "We compute a periodicity metric, Q, by assessing how close the
light-curve points are to the systematic noise floor before and after the
phased trend is subtracted from the light curve:
Q=(rms2resid-σ2)/(rms2raw-σ2),
where rmsraw and rmsresid are the rms values of the raw light curve
and the phase-subtracted light curve, respectively, whereas σ is
the estimated uncertainty including the systematics".
Note (9): For the objects where there are both [3.6] and [4.5] data, we can
calculate the Stetson index (Stetson 1996PASP..108..851S 1996PASP..108..851S), given by
Equation (1) in the paper (see Section 4.2).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- SSTYSV Designation within the Spitzer Space Telescope
(SST) Young Stellar Object VARiability
(YSOVAR) program (HHMMSS.ss+DDMMSS.s; J2000)
(cat) (1)
20- 32 A13 --- Sample Sample
34-202 A169 --- Note Notes
--------------------------------------------------------------------------------
Note (1): Variable with amplitude >0.4mag in either channel.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- SSTYSV Designation within the Spitzer Space Telescope
(SST) Young Stellar Object VARiability
(YSOVAR) program (HHMMSS.ss+DDMMSS.s; J2000)
(cat)
20- 22 A3 --- Class0 Identified as Class O? (yes or no)
24- 26 A3 --- Jet Jet driver? (yes or no)
28- 29 A2 --- Cl Our class (I or II)
31- 33 A3 --- CY Is this Cryo-to-YSOVAR (CY) variable? (yes or
no)
35- 37 A3 --- Var Variable in either channel over the YSOVAR
campaign? (yes or no)
39- 43 F5.2 mag [3.6] [9.8/17.5]? Spitzer/IRAC 3.6µm band
magnitude from the cryogenic era
45- 49 F5.2 mag [4.5] [7.8/15.8] Spitzer/IRAC 4.5µm band
magnitude from the cryogenic era
51-201 A151 --- Note Notes
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Var Indicates a variable over the YSOVAR campaign
("Detected"), or an object not detected as
variable over the YSOVAR campaign
14- 31 A18 --- SSTYSV Designation within the Spitzer Space Telescope
(SST) Young Stellar Object VARiability
(YSOVAR) program (HHMMSS.ss+DDMMSS.s; J2000)
33- 79 A47 --- OName Other(s) name(s)
81- 85 A5 --- Fig Figure number
87-327 A241 --- Note Notes
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 30-Jun-2016