J/ApJS/235/43 The 2nd MSFRs Omnibus X-ray Catalog (MOXC2) (Townsley+, 2018)
The Massive Star-forming Regions Omnibus X-Ray Catalog, second installment.
Townsley L.K., Broos P.S., Garmire G.P., Anderson G.E., Feigelson E.D.,
Naylor T., Povich M.S.
<Astrophys. J. Suppl. Ser., 235, 43 (2018)>
=2018ApJS..235...43T 2018ApJS..235...43T
ADC_Keywords: Star Forming Region; H II regions; X-ray sources
Keywords: H II regions ; stars: early-type ; stars: formation ; X-rays: stars
Abstract:
We present the second installment of the Massive Star-forming Regions
(MSFRs) Omnibus X-ray Catalog (MOXC2), a compilation of X-ray point
sources detected in Chandra/ACIS observations of 16 Galactic MSFRs and
surrounding fields. MOXC2 includes 13 ACIS mosaics, three containing a
pair of unrelated MSFRs at different distances, with a total catalog
of 18396 point sources. The MSFRs sampled range over distances of
1.3kpc to 6kpc and populations varying from single massive protostars
to the most massive Young Massive Cluster known in the Galaxy. By
carefully detecting and removing X-ray point sources down to the
faintest statistically significant limit, we facilitate the study of
the remaining unresolved X-ray emission. Through comparison with
mid-infrared images that trace photon-dominated regions and ionization
fronts, we see that the unresolved X-ray emission is due primarily to
hot plasmas threading these MSFRs, the result of feedback from the
winds and supernovae of massive stars. The 16 MSFRs studied in MOXC2
more than double the MOXC1 sample, broadening the parameter space of
ACIS MSFR explorations and expanding Chandra's substantial
contribution to contemporary star formation science.
Description:
The Chandra/ACIS observations (spanning 2001 October to 2016 June)
used for MOXC2 are summarized in Table 2. All of these data sets are
available in the Chandra archive.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 150 16 The Massive Star-forming Regions (MSFRs)
Omnibus X-ray Catalog (MOXC2) targets
table2.dat 154 60 Log of Chandra observations
moxc2.dat 535 18396 MOXC2 X-ray sources and properties
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Description of file:
In the FTP section, xray_properties.fits.gz is the original MOXC2
catalog in FITS format (gzip).
See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
IX/45 : The Chandra Source Catalog, Release 1.1 (Evans+ 2012)
IX/57 : The Chandra Source Catalog (CSC), Release 2.0 (Evans+, 2019)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/ApJ/454/151 : OB Associations of the Northern Milky Way (Massey+ 1995)
J/ApJ/566/945 : Massive star forming regions at 1.2mm (Beuther+, 2002)
J/A+A/426/119 : 1.2mm mapping of RCW 106 Giant MoC (Mookerjea+, 2004)
J/A+A/440/121 : K magnitudes of OB stars in UCHIIs (Bik+, 2005)
J/ApJS/160/319 : COUP: observations and source lists (Getman+, 2005)
J/A+A/438/1163 : Catalogue of Open Cluster Data (COCD) (Kharchenko+, 2005)
J/ApJ/635/560 : New star clusters in the GLIMPSE survey (Mercer+ 2005)
J/ApJ/649/759 : Bubbles in the galactic disk (Churchwell+, 2006)
J/A+A/445/971 : Mid-infrared images of W75N (Persi+, 2006)
J/ApJ/670/428 : Bubbles in the galactic disk. II. (Churchwell+, 2007)
J/ApJ/665/1297 : X-ray sources around G12.82-0.02 (Helfand+, 2007)
J/A+A/472/835 : JHKs and GLIMPSE photometry of RCW 120 (Zavagno+, 2007)
J/A+A/477/147 : X-ray sources in Westerlund 1 (Clark+, 2008)
J/A+A/496/177 : JHKs and GLIMPSE photometry of RCW 120 (Deharveng+, 2009)
J/AJ/138/227 : Stellar clusters in NGC 6334 complex (Feigelson+, 2009)
J/ApJ/694/546 : IR dust bubbles. II. YSOs model parameters (Watson+, 2009)
J/ApJ/708/1760 : Flux estimations of faint X-ray sources (Getman+, 2010)
J/ApJ/714/L285 : YSO candidates in M17 SWex (Povich+, 2010)
J/ApJS/194/2 : Chandra Carina Complex Project (CCCP) catalog (Broos+, 2011)
J/ApJS/194/5 : Carina OB stars in the CCCP catalog (Gagne+, 2011)
J/ApJS/194/7 : X-ray properties of O and B stars in Carina (Naze+, 2011)
J/ApJS/194/14 : A Pan-Carina YSO catalog (Povich+, 2011)
J/ApJS/194/15 : CCCP: Carina's diffuse X-ray emission (Townsley+, 2011)
J/MNRAS/419/1887 : Young stellar objects in NGC 6823 (Riaz+, 2012)
J/A+A/545/A51 : 1.4mm & 3mm interferometry of IRAS 19410+2336 (Rodon+, 2012)
J/A+A/538/A142 : OB stars in NGC 6334 and NGC 6357 (Russeil+, 2012)
J/ApJS/209/32 : Probable young stars in the MYStIX project (Broos+, 2013)
J/ApJS/209/27 : MYStIX: the Chandra X-ray sources (Kuhn+, 2013)
J/MNRAS/435/400 : ATLASGAL. Compact HII regions (Urquhart+, 2013)
J/ApJ/778/96 : Spitzer and NEWFIRM observations of NGC 6334 (Willis+, 2013)
J/ApJS/212/13 : ChIcAGO. I. Sample and initial results (Anderson+, 2014)
J/A+A/572/A63 : Intensity maps in W33 (Immer+, 2014)
J/MNRAS/443/3218 : NGC 7538 IRS 1-3 and IRS 9 sources (Mallick+, 2014)
J/ApJS/215/15 : SMaSH+: observations and companion detection (Sana+, 2014)
J/ApJS/213/1 : The MSFRs Omnibus X-ray Catalog (MOXC) (Townsley+, 2014)
J/ApJS/219/41 : VLA & Chandra obs. of IRAS20126+4104 region (Montes+, 2015)
J/AJ/152/31 : Spectral classif. of OVz stars from GOSSS (Arias+, 2016)
J/ApJS/224/4 : GOSSS III. Additional O-type systems (Maiz Apellaniz+, 2016)
J/A+A/587/A135 : Halpha images of NGC 6334 and NGC 6357 (Russeil+, 2016)
J/A+A/605/A61 : NGC 7538 IRS1 VLA maps in CH3OH and NH3 (Beuther+, 2017)
J/ApJ/843/33 : SOFIA Massive Star Formation Survey. I. (De Buizer+, 2017)
J/A+A/600/A93 : Multiwavelength fluxes of RCW120 (Figueira+, 2017)
J/ApJS/229/28 : SFiNCs: X-ray, IR and membership catalogs (Getman+, 2017)
J/MNRAS/467/2943 : NGC 7538 region YSOs (Sharma+, 2017)
J/A+A/602/A77 : HOBYS: 46 MDCs found in NGC 6334 (Tige+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- MSFR Massive star forming region name
17- 22 F6.2 deg GLON [10.3/351] Galactic longitude
24- 28 F5.2 deg GLAT [-0.5/3.7] Galactic latitude
30- 31 I2 h RAh Hour of right ascension (J2000)
33- 34 I2 min RAm Minute of right ascension (J2000)
36- 39 F4.1 s RAs Second of right ascension (J2000)
41 A1 --- DE- Sign of declination (J2000)
42- 43 I2 deg DEd Degree of declination (J2000)
45- 46 I2 arcmin DEm Arcminute of declination (J2000)
48- 49 I2 arcsec DEs Arcsecond of declination (J2000)
51- 54 F4.2 kpc Dist [1.3/6] Distance from the literature or
estimated in this paper
56- 59 F4.2 arcmin/pc Scale [0.5/2.7] Image scale assuming "Dist" value
61- 63 I3 mag Av [3/200] Approximate average absorption (1)
65- 66 I2 ks Exp [8/79] Nominal exposure time (2)
68- 72 F5.2 [10-7W] logLtc [29.6/31.8] log of total band (0.5-8keV)
luminosity, corrected for extinction (3)
74- 76 F3.1 Msun M50 [0.3/1.8]? Limiting mass M50%
corresponding to limiting luminosity Ltc
77 A1 --- f_M50 b: bright (4)
79- 82 I4 --- Nx [288/4674] Total number of X-ray point
sources found across the entire mosaic
84- 94 A11 --- n_Nx Same X-ray point sources for the MSFR
cited in this column
96-150 A55 --- r_Dist Reference(s)
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Note (1): Approximate average absorption to the target, estimated from a
variety of literature sources. Most MSFRs have highly variable and
spatially complex obscuration, so this value should be used only as a
rough indicator.
Note (2): A typical exposure time for the main MSFRs. Most mosaics have a
wide range of exposures; detailed exposure maps are shown in Section 4.
Note (3): A rough limiting luminosity where the brighter half of the X-ray
population is sampled.
Note (4): For shallow observations, this limit is higher than pre-MS masses,
so only "bright" sources (some massive stars and intermediate-mass
pre-MS stars) are expected.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- MSFR Massive star forming region name
17- 33 A17 --- Target Chandra target name
35- 39 I5 --- ObsID [1827/18876] Chandra ObsID
41- 56 A16 "datime" Date Start time of the observation (UT date)
58- 62 I5 s Exp [1015/62810] Exposure time (1)
64- 65 A2 --- CCD Aimpoint CCD (2)
67- 68 I2 h RAh Aimpoint hour of right ascension (J2000) (2)
70- 71 I2 min RAm Minute of right ascension (J2000)
73- 77 F5.2 s RAs Second of right ascension (J2000)
79 A1 --- DE- Aimpoint sign of declination (J2000) (2)
80- 81 I2 deg DEd Aimpoint degree of declination (J2000) (2)
83- 84 I2 arcmin DEm Arcminute of declination (J2000)
86- 89 F4.1 arcsec DEs Arcsecond of declination (J2000)
91- 93 I3 deg Roll [5/358] Roll angle
95- 99 A5 --- Mode ACIS observing mode (3)
101-106 I06 --- Det [123/235678] Detectors (4)
108-124 A17 --- PI Personal investigator
126-154 A29 --- TGAIN ACIS Time-Dependent Gain file used for
calibration of event energies (5)
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Note (1): Exposure times are the net usable times after various filtering
steps are applied in the data reduction process. For the following
ObsIDs, we discarded exposure time as noted to remove periods of high
instrumental background: 2573 (35%), 4591 (7%), 6224 (1%), 1868 (56%),
5373 (2%), 5411 (4%). The time variability of the ACIS background is
discussed in Section 6.16.3 of the Chandra Proposers' Observatory
Guide (http://asc.harvard.edu/proposer/POG/) and in the ACIS
Background Memos at
http://asc.harvard.edu/cal/Acis/Cal_prods/bkgrnd/current/
Note (2): The aimpoints (given in celestial coordinates) are obtained from
the satellite aspect solution before astrometric correction is applied.
Note (3): ACIS observing modes are described in Section 6.12 of the Chandra
Proposers' Observatory Guide (http://asc.harvard.edu/proposer/POG/).
Note (4): The layout of the 10 CCD detectors (numbered 0 through 9 here) in
the ACIS focal plane is shown in Section 6.1 of the Chandra Proposers'
Observatory Guide (http://asc.harvard.edu/proposer/POG/).
Note (5): Version N0010 of the Optical Blocking Filter model was used for
the calibration of Ancillary Response Files and exposure maps.
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Byte-by-byte Description of file: moxc2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- MSFR Name of the massive star forming region
(REGIONNAME)
17- 34 A18 --- CXOU X-ray source name in IAU format
(HHMMSS.ss+DDMMSS.s; J2000) (Name) (1)
36 A1 --- f_CXOU p: source exhibiting photon pile-up;
column added by CDS (see Note 7)
38- 52 A15 --- Label X-ray source name used within the project (2)
54- 63 F10.6 deg RAdeg [244.5/348.9] Right ascension (J2000) (1)
65- 74 F10.6 deg DEdeg [-51.2/61.8] Declination (J2000) (1)
76- 80 F5.3 arcsec ePos [0.01/5.7] 1-σ error circle around
(RAdeg,DEdeg) (PosErr)
82- 98 A17 --- PosType Algorithm used to estimate position
(Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B Section 7.1)
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100-107 F8.6 --- no-m [0/0.01] Smallest of no-t, no-s and no-h
(ProbNoSrc_MostValid) (3)
109-116 F8.6 --- no-t [0/0.5] p-value for no-source hypothesis
in the total (0.5-8 keV) energy band
(ProbNoSrc_t) (4)
118-125 F8.6 --- no-s [0/1]? p-value for no-source hypothesis
in the soft (0.5-2 keV) energy band
2012A&A...539A..79R 2012A&A...539A..79R (ProbNoSrc_s) (4)
127-134 F8.6 --- no-h [0/1]? p-value for no-source hypothesis
in the hard (2-8 keV) energy band
(ProbNoSrc_h) (4)
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136-143 F8.6 --- KS-S [0/1]? smallest p-value under the null
hypothesis (no variability within each
single ObsID) for the Kolmogorov-Smirnov
test on the timestamps of each ObsID's event
list (ProbKS_single) (5)
145-152 F8.6 --- KS-M [0/1]? p-value under the null hypothesis
(no variability) for the Kolmogorov-Smirnov
test on the timestamps of the multi-ObsID
event list (ProbKS_merge) (5)
154-161 F8.6 --- Chi2 [0/1]? p-value under the null hypothesis
(no variability) for the χ2 test on
the single-ObsID measurements of Flux-t
(ProbChisq_PhotonFlux)
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163-171 F9.2 s ExpNom [1015/147545] Total exposure in merged
observations (ExposureTimeNominal)
173-180 F8.6 --- ExpFrac [0.07/1] Fraction of ExpNom source was
observed (ExposureFraction) (6)
182-189 F8.6 ct Ct [0/0.5] 0.5-8keV rate in 3x3 CCD pixel cell
in count/frame (RateIn3x3Cell) (7)
191 I1 --- Nobs [1/4] Total number of observations extracted
(NumObsIDs)
193 I1 --- Nph [1/4] Number of observations merged to
estimate photometry properties (NumMerged)
195-202 F8.6 --- Fdis [0/1] Fraction of exposure discarded to
optimize merge (MergeBias)
204-212 F9.6 arcmin b_theta [0.01/25] Smallest value of θ (Theta_Lo)
214-222 F9.6 arcmin theta [0.04/25] Average off-axis angle θ for
merged observations (Theta)
224-232 F9.6 arcmin B_theta [0.04/27.4] Largest value of θ
(Theta_Hi)
234-241 F8.6 --- PSFf [0.3/1] Average PSF fraction at 1.49keV for
merged observations (PsfFraction)
243-254 F12.6 pix2 Area [0.7/31950] Average aperture area for merged
observations in (0.492arcsec)2 units
(SrcArea)
256-263 F8.6 --- aglow [0/0.7]? Suspected afterglow fraction,
0.5-8keV (AfterglowFraction) (8)
265-268 I4 ct Cts-t [0/8598] Extracted 0.5-8keV counts in merged
apertures (SrcCounts_t)
270-273 I4 ct Cts-s [0/2189] Extracted 0.5-2keV counts in merged
apertures (SrcCounts_s)
275-278 I4 ct Cts-h [0/8320] Extracted 2-8keV counts in merged
apertures (SrcCounts_h)
280-291 F12.6 --- bgScl [0.4/13937] Scaling of background extraction
(BkgScaling)
293-296 I4 ct Bcts-t [3/6732] Extracted 0.5-8keV counts in merged
background regions (BkgCounts_t)
298-301 I4 ct Bcts-s [0/1088] Extracted 0.5-2keV counts in merged
background regions (BkgCounts_s)
303-306 I4 ct Bcts-h [0/6543] Extracted 2-8keV counts in merged
background regions (BkgCounts_h)
308-318 F11.6 ct Ncts-t [-0.4/8553] Net 0.5-8keV counts in merged
apertures (NetCounts_t)
320-330 F11.6 ct Ncts-s [-10.2/2183] Net 0.5-2keV counts in merged
apertures (NetCounts_s)
332-342 F11.6 ct Ncts-h [-20.1/8278] Net 2-8keV counts in merged
apertures (NetCounts_h)
344-354 F11.6 ct b_Ncts-t [0/8460]? 1-σ lower bound on Ncts-t
(NetCountsLot) (9)
356-365 F10.5 ct B_Ncts-t [1/8647] 1-σ upper bound on Ncts-t
(NetCountsHit) (9)
367-376 F10.5 ct b_Ncts-s [0/2136]? 1-σ lower bound on Ncts-s
(NetCountsLos) (9)
378-387 F10.5 ct B_Ncts-s [0/2230] 1-σ upper bound on Ncts-s
(NetCountsHis) (9)
389-398 F10.5 ct b_Ncts-h [0/8186]? 1-σ lower bound on Ncts-h
(NetCountsLoh) (9)
400-409 F10.5 ct B_Ncts-h [0.5/8370] 1-σ upper bound on Ncts-h
(NetCountsHih) (9)
411-418 F8.4 cm2.ct/ph Area-t [12/293] Mean effective area (ARF value)
in cm2.count/photon in 0.5-8keV
(MeanEffectiveArea_t) (10)
420-427 F8.4 cm2.ct/ph Area-s [16.5/515] Mean effective area (ARF value)
in cm2.count/photon in 0.5-2keV
(MeanEffectiveArea_s) (10)
429-436 F8.4 cm2.ct/ph Area-h [10.4/238] Mean effective area (ARF value)
in cm2.count/photon in 2-8keV
(MeanEffectiveArea_h) (10)
438-443 F6.4 keV Emed-t [0.5/7.6]? Median 0.5-8keV energy, observed
spectrum (MedianEnergy_t)
445-450 F6.4 keV Emed-s [0.5/2]? Median 0.5-2keV energy, observed
spectrum (MedianEnergy_s)
452-457 F6.4 keV Emed-h [2/8]? Median 2-8keV energy, observed
spectrum (MedianEnergy_h)
459-470 E12.6 ph/cm2/s Flux-t [-7.7e-8/0.0014] Incident total (0.5-8keV)
photon flux: NCts-t/Area-t/ExpNom
(PhotonFlux_t) (11)
472-483 E12.6 ph/cm2/s Flux-s [-2.2e-6/0.00011] Incident soft (0.5-2keV)
photon flux: NCts-s/Area-s/ExpNom
(PhotonFlux_s) (11)
485-496 E12.6 ph/cm2/s Flux-h [-1.7e-5/0.0016] Incident hard (2-8keV)
photon flux: NCts-h/Area-h/ExpNom
(PhotonFlux_h) (11)
498-509 E12.6 mW/m2 EFlx-t [0/1.1e-11] Total (0.5-8keV) energy flux max
(EFlxs>0)+max(EFlxh,0) (EnergyFlux_t)(12)
511-522 E12.6 mW/m2 EFlx-s [7.4e-20/2.6e-13]? Soft (0.5-2keV) apparent
energy flux (EnergyFlux_s) (12)
524-535 E12.6 mW/m2 EFlx-h [2.5e-20/1.1e-11]? Hard (2-8keV) apparent
energy flux (EnergyFlux_h) (12)
--------------------------------------------------------------------------------
Note (1): Name and position, derived from the ObsIDs that minimize the position
uncertainty (Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B -- Section 6.2 and 7.1)
Note (2): Source "labels" identify each source during data analysis, as the
source position (and thus the Name) is subject to change.
Note (3): Validity metrics, derived from a pre-defined set of ObsID combinations
(Section 2.2.3)
Note (4): Smallest p-value under the no-source null hypothesis
(Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B Section 4.3) among validation merges.
In statistical hypothesis testing, the p-value is the probability of
obtaining a test statistic at least as extreme as the one that was
actually observed, when the null hypothesis is true. The p-value of
the observed extraction under the no-source hypothesis is calculated
by the method described by (Weisskopf+ 2007ApJ...657.1026W 2007ApJ...657.1026W --Appendix A2),
which is derived under the assumption that X-ray extractions follow
Poisson distributions.
Note (5): See (Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B --Section 7.6) for a description of
the "KS-s" (ProbKS_single) and "KS-m" ProbKS_merge variability
indexes, and caveats regarding possible spurious indications of
variability using the ProbKS_merge index.
Note (6): Due to dithering over inactive portions of the focal plane, a
Chandra source often is not observed during some fraction of the
nominal exposure time (See http://cxc.harvard.edu/ciao/why/dither.html).
The reported quantity is FRACEXPO, produced by the CIAO tool mkarf.
Note (7): ACIS suffers from a nonlinearity at high count rates known as photon
pile-up, described in Section 3.2 below. RateIn3x3Cell is an estimate
of the observed count rate falling on an event detection cell of size
3x3 ACIS pixels, centered on the source position. When RateIn3x3Cell
>0.05 (count/frame), the reported source properties may be biased by
pile-up effects. See Table 4 and column "f_CXOU" for a list of MOXC2
sources with significant pile-up. All source properties in this table
are not corrected for pile-up effects.
Note (8): Some background events arising from an instrumental effect known
as "afterglow" (http://cxc.harvard.edu/ciao/why/afterglow.html) may
contaminate source extractions, despite careful procedures to identify
and remove them during data preparation (Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B
--Section 3). After extraction, we attempt to identify afterglow
events using the AE tool aeafterglowreport, and report the fraction
of extracted events attributed to afterglow; see the ACIS Extract
manual (http://personal.psu.edu/psb6/TARA/ae_users_guide.html).
Note (9): Confidence intervals (68%) for NCts quantities are estimated
by the CIAO tool aprates (http://asc.harvard.edu/ciao/ahelp/aprates.html).
Note (10): The ancillary response file (ARF) in ACIS data analysis represents
both the effective area of the observatory and the fraction of the
observation for which data were actually collected for the source (ExpFrac).
Note (11): PhotonFlux = (NetCounts/MeanEffectiveArea/ExposureTimeNominal)
(Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B --Section 7.4).
Note (12): EnergyFlux = 1.602x10-9(erg/keV)xPhotonFluxxMedianEnergy
(Getman+ 2010ApJ...708.1760G 2010ApJ...708.1760G --Section 2.2).
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History:
From electronic version of the journal
References:
Townsley et al. MOXC1. 2014ApJS..213....1T 2014ApJS..213....1T Cat. J/ApJS/213/1
Townsley et al. MOXC3. 2019ApJS..244...28T 2019ApJS..244...28T Cat. J/ApJS/244/28
(End) Emmanuelle Perret [CDS] 20-Mar-2020