Chandra ObsID: 22983

C H A N D R A S C I E N C E C E N T E R
O B S E R V A T I O N C A T A L O G

OBSID:
22983 Title:
Star formation in starburst: a deep ACIS-I observation of Westerlund 1

Investigator:
Guarcello Observer:
Drake, Jeremy Phone:
6174967850 Email:
jdrake@cfa.harvard.edu

Target Name:
Westerlund 1 Sequence Number:
201285 Instrument:
ACIS-I Grating:
NONE SI Mode:
TE_006E6B Raster Scan:
N Annotated DOT:
JUN0721a

Proposal Number:
21200267 Right Ascension:
251.773 Declination:
-45.8608 Status:
archived Start Date:
2021-06-09 09:56:05

Category:
STARS AND WD Type:
GO AO Cycle:
21 Dither Flag:
Y Y Offset:
0 Z Offset:
0

Est. Count Rate:
2.5e-05 Order-1 Count Rate: Exposure Time:
27.5 Time Remaining:
28.082 Reqd Start Time: Reqd Stop Time:

Period: Epoch: Start of Period: End of Period: PS Margin: PE Margin: Max Segments:
0

ACIS Mode:
TE Standard?:
No BEP Mode:
VF

On-Chip Summing?:
No Row Sum: Column Sum: Frame Time:

Subarray Mode:
NONE Starting Row:
0 Row Count:
1023 Subarray Frame Time:

Duty Cycle?:
No Cycle Count:
0 Primary Exp Time: Secondary Exp Time:

Event Filter?:
No Filter Threshold: Filter Range: Bias Requested?:
No Bias Frequency: Bias After?:
No Spatial Window?:
No

Abstract:
Typical star forming regions (SFRs) in the Milky Way have a small fraction of the stellar content of starburst clusters, which are typical of the starburst galaxies and represent the most extreme star forming environment. Westerlund 1 (Wd1) is the closest starburst cluster to the Sun and thus the best laboratory for extending our knowledge on star and planet formation and early stellar evolution to extreme starburst conditions. We propose a 1Msec Chandra/ACIS-I observation of Wd1 in order to unveil its low mass stellar population, and investigate a star forming environment which is so far unexplored in X-rays in the low mass regime. The proposed observation will advance our understanding in the key area of star formation, the evolution of stars and that massive stellar clusters.

Remarks:
This set of XVP observations of Westerlund 1 requires coordinate specification that depends on the satellite roll angle. The coordinates to use within a given time interval are listed in the table below. Period beginning Mid-interval Target Coordinates Yr Mo Day MJD Roll RA Dec 2020 1 20 58868. 100.4 251.78153 -45.841157 2020 2 3 58882. 93.0 251.78704 -45.843191 2020 2 17 58896. 86.8 251.77342 -45.844108 2020 3 2 58910. 70 251.77852 -45.843971 2020 4 27 58966. 50.2 251.7797 -45.846705 2020 5 11 58980. 38.1 251.78447 -45.850724 2020 5 18 58987. 27.1 251.78839 -45.852774 2020 5 25 58994. 13.4 251.78178 -45.853782 2020 6 1 59001. 357.1 251.77054 -45.854003 2020 6 8 59008. 332.5 251.77269 -45.860837 2020 6 22 59022. 307.5 251.76349 -45.862732 2020 7 6 59036. 291.9 251.75819 -45.861364 2020 7 20 59050. 281.7 251.75915 -45.858784 2020 8 3 59064. 274.4 251.75231 -45.85822 2020 8 17 59078. 268.2 251.75231 -45.85412 2020 8 31 59092. 262.7 251.75055 -45.852069 2020 9 14 59106. 254 251.74987 -45.86023 2020 10 12 59134. 244.0 251.74987 -45.853806

psci Run:
26 Processing Date:
Jun 18 2021 psci Directory:
/nfs/maaxnew/r3/fb/acis116a/acis116.log

OBSID:
22983 SIM Mode:
ACIS-I OTG Mode:
NONE Seq Number:
201285 Target Name:
Westerlund_1 AO:
21

Start VCDU:
82754:056 Start Time (UTC):
160:36969.997 Stop Time (UTC):
160:65063.426 Kilosecs:
28.1 % Frames:
100.0 # CCDs:
I4

# Frames:
8944 # Events:
822406 Events/sec:
29 PSCI errors:
0 % drops:
0.0 Bias Errs:
1 FP Temp:
-118.3

Parameter Block:
0x006e6034 Window Block:
- # Windows:
0 FEP Mode:
Te5x5 BEP Mode:
F Start Row:
0 # Rows:
1024

Primary Exposure:
31 Secondary Exposure:
0 Duty Cycle:
0 Summing?:
No Bias?:
Yes Trickle?:
Yes Bias Run:
26

pgf@space.mit.edu Mon Mar 31 10:36:39 EST 2025