Justification may be needed for use of certain lifetime positions with G160M. See "Errors and Warnings" for more details.Final submission of the OB+BH proposal-1580406270Assigned ID: 3406
----- Attempting Submission 1 (Fri Mar 25 18:43:27 GMT 2022) -----
HST Phase I Proposal 3406 successfully submitted.
Receipt: # 3406-1
----- Attempting Submission 2 (Fri Mar 25 21:46:11 GMT 2022) -----The proposal includes the use of the COS G160M[1611] setting for observations of less than half of an orbit.
As indicated in the COS handbook, this is sufficient to for using the LP4 lifetime position.
This justification is also stated in the PDF of the proposal.For the best data quality, it is generally required to use all four FP-POS positions when observing at a given COS cenwave. See the COS Instrument Handbook for exceptions that may apply to observations with G130M/1291 or G160M.
An FUV exposure with Wavelength 1055 or 1096 has been specified with SEGMENT=B.
An FUV exposure with Wavelength 1055 or 1096 has been specified with SEGMENT=B.
For the best data quality, it is generally required to use all four FP-POS positions when observing at a given COS cenwave. See the COS Instrument Handbook for exceptions that may apply to observations with G130M/1291 or G160M.Using the suggestions from the contact scientist, changed the modes in exposures 4 and 5 of Visit 3 from “ACCUM” to “TIME-TAG”.-794613464----- Attempting Submission 2 (Thu Jul 14 17:08:39 GMT 2022) -----
HST Phase II Proposal 17074 successfully submitted.
Receipt: # 17074-2
----- Attempting Submission 3 (Sun Aug 07 13:43:31 GMT 2022) -----
----- Attempting Submission 4 (Mon Aug 29 10:16:13 GMT 2022) -----
HST Phase II Proposal 17074 successfully submitted.
Receipt: # 17074-4
----- Attempting Submission 5 (Thu Sep 08 09:13:48 GMT 2022) -----
HST Phase II Proposal 17074 successfully submitted.
Receipt: # 17074-5
----- Attempting Submission 6 (Fri Sep 23 15:52:43 GMT 2022) -----
HST Phase II Proposal 17074 successfully submitted.
Receipt: # 17074-6
----- Attempting Submission 7 (Tue Oct 04 14:01:45 GMT 2022) -----Since we are observing the first target in COS 130M /1096 setting, but only with segment B, additional wavecal exposure are needed.
So I have included WCA exposures with both segments at FP-POS =1 and 3 before and after the corresponding science exposures. This would result in the highest S/N possible while still effectively dithering over this low response region near the O VI lines.
Since FP-POS =all is not allowed in COS G130M/1291, I have selected FP-POS=3 and FP-POS=4 for each exposures.
Using the suggestions from the contact scientist I change the Availability field from Supported to Available and then changed LIFETIME-POS aacordingly.Smoking guns in massive binary evolution: The hunt for Black Holes and Stripped StarsWith the detection of gravitational waves from merging compact objects, a new observational window onto the fates of massive stars has been opened. To explain the observed mergers of compact objects, we need accurate knowledge about the evolution of massive binary stars. Yet, current population synthesis calculations often yield puzzling results, as they predict certain types of stellar systems in large numbers, which are rarely observed. Whether this is due to observational challenges or due to errors in the underlying evolutionary models, is one of the major open questions in massive star research.
In this proposal, we tackle two crucial stages of massive binary evolution that are predicted in large numbers, but so far rarely observed: Systems containing an OB-star accompanied by an X-ray-quiet black hole (BH) and systems where a hot, envelope-stripped star is outshined by its OB-type companion. In both cases, the (compact) companion hardly leaves any trace in the optical beyond a suspicious, small He II disk-like emission. To identify the nature of the companion and distinguish between a BH and a stripped-star companion, UV spectroscopy is the only viable tool. With the unique capabilities of the HST, we will perform a pilot study for two prototypical systems in the Galaxy and the LMC that harbor either a BH or a stripped star companion. By determining the presence of tracing ions and the wind parameters of the stars, our study will confirm or deny the existence of the presently only known dormant BH in the Milky Way, marking an anchor point for our understanding of massive binary evolution and defining a framework for future observations of stripped stars.We are observing a bright Galactic B star MWC656 with Vmag~8.8 using STIS and COS. For STIS E140M and E230M settings, ETC only gives a warning about lower buffer time. In COS 130M /1096 setting, it gives a count rate warning in segment A.
But we are planning to observe only in segment B. Our main aim is to look at O IV line at 1032-38 A, which is important for our science case.
Since the wavecal lines are too faint for Segment B, and only show up on Segment A, we added additional wavecal exposure before and after the science exposure.
When I run BOT for this object, it gives a warning in all exposures. However, the details of this warning consider an O5 spectral type for this star whereas the actual spectral type is B1-2. I hope this is not a problem.
The second target is an LMC O star, which will be observed using COS/FUV. In the COS130M/ 1291 setting (both segments), all FP-POS setting is not available. So I opted for two different exposures with FP-POS=3 and 4. However, it still gives a warning in APT. In COS 160M/1611 we chose both segments and all FP-POS.
Each target has two consecutive orbits planned to reduce the overheads. In all spectral settings, we aim for S/N ~30 except COS 130M /1096 segment B.The team consists of experts and students working in all subjects relevant for the proposal, specifically stellar and binary evolution, stellar winds, and massive star spectroscopy. The primary modeling tools for the analysis of the observations will be PoWR, a non-LTE stellar atmosphere code which is actively used for the analysis of OB stars. The PI and all Co-Is have detailed experience with non-LTE atmosphere modelling. A. Sander, H. Todt, and W.-R. Hamann are lead developers of PoWR.
Dr. Ramachandran (PI) has published spectroscopic studies of OB stars in the SMC, LMC and the Magellanic Bridge. She further has experience in studying high mass X-ray binaries (HMXBs) with black holes. Prof. Dr. W.-R. Hamann is a leading expert in UV spectroscopy of massive stars and stellar wind modeling. Prof. Dr. Oskinova has led many large observing campaigns in optical, UV, and X-rays to spectroscopically study massive stars and HMXBs. Dr. Sander is an expert in hydrodynamic modeling of stellar winds, including winds from helium stars and donors in HMXBs. D. Pauli is a PhD student who works on the analysis of early-type massive binaries in the SMC. The PhD students M. Bernini Peron and R. Lefever are working on evolved B stars and Wolf-Rayet winds respectively. Moreover, D. Pauli, and V. Ramachandran have experience in modelling the binary evolution of massive stars with the publicly available MESA code.Stellar Physics and Stellar Types6falsefalsetruefalsefalsefalsefalseAVAILABLESTARB0-B2 III-INOCoordinates and proper motions are taken from Gaia DR3J2000J2000Gmag=8.7EXT-STARMAIN SEQUENCE ONOCoordinates and proper motions are taken from Gaia DR3J2000J2000Gmag=14.87COS/FUVSpectroscopicNoNoG130M1096COS/FUVSpectroscopicNoNoG130M1300COS/FUVSpectroscopicNoNoG160M1611STIS/FUV-MAMASpectroscopicNoNoE140M1425STIS/NUV-MAMASpectroscopicNoNoE230M2124COS/FUVSpectroscopicNoNoG130M1055C:\work\proposals\HST2022\BHOB\OP-cache\OBBHupdateSep23-v01.xmlThe scheduling data was generated by CASM 30.3.CASM was run in Phase II mode.(Tic-Visit
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