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OBSID:
24392
 Title:
The LMXB population of NGC 3998: Testing for an extreme IMF    
Investigator:
Zepf
 Observer:
Zepf, Steve
 Phone:
5178845512
 Email:
zepf@msu.edu
Target Name:
NGC 3998
 Sequence Number:
601539
 Instrument:
ACIS-S
 Grating:
NONE
 SI Mode:
TE_004A4B
 Raster Scan:
N
 Annotated DOT:
SEP0621a

Proposal Number:
22620521
 Right Ascension:
179.484
 Declination:
55.4536
 Status:
archived
 Start Date:
2021-09-12 00:00:50
Category:
NORMAL GALAXIES
 Type:
GO
 AO Cycle:
22
 Dither Flag:
Y
 Y Offset:
0
 Z Offset:
0
Est. Count Rate:
0.0001
 Order-1 Count Rate:

 Exposure Time:
20
 Time Remaining:
19.852
 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
 Dropped Chip Count:
0
 Optional Chips:
I2 I3 S1 S2 S4
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:
We propose to observe the LMXB population of NGC 3998, a local early-type galaxy. Kinematic studies of this galaxy have shown that it has an extreme mass-to-light ratio. We will utilize the galaxy's LMXB population to trace the populations of compact objects in the galaxy. These data will provide the first direct test of whether this high M/L ratio is the result of an extremely top heavy stellar IMF. Such extreme IMFs have been proposed and, if confirmed, would have broad astrophysical implications.

Remarks:
A 15 ks ACIS-S observation exists for this galaxy. As discussed in the justification, these data are too shallow to achieve our goals. We will add these data to the new observations.

psci Run:
66
 Processing Date:
Sep 26 2021
 psci Directory:
/nfs/maaxnew/r3/fc/acis117b/acis117.log
OBSID:
24392
 SIM Mode:
ACIS-S
 OTG Mode:
NONE
 Seq Number:
601539
 Target Name:
NGC_3998
 AO:
22
Start VCDU:
69761:088
 Start Time (UTC):
255:01426.345
 Stop Time (UTC):
255:21290.577
 Kilosecs:
19.9
 % Frames:
100.0
 # CCDs:
I6
# Frames:
6129
 # Events:
1092215
 Events/sec:
54
 PSCI errors:
0
 % drops:
0.0
 Bias Errs:
0
 FP Temp:
-116.2
Parameter Block:
0x004a4034
 Window Block:
-
 # Windows:
0
 FEP Mode:
Te5x5
 BEP Mode:
F
 Start Row:
0
 # Rows:
1024
Primary Exposure:
32
 Secondary Exposure:
0
 Duty Cycle:
0
 Summing?:
No
 Bias?:
Yes
 Trickle?:
Yes
 Bias Run:
66

pgf@space.mit.edu Thu Apr 3 20:00:53 EST 2025