0 Assigned ID: 2653 ----- Attempting Submission 1 (Thu Jan 06 02:15:00 GMT 2022) ----- HST Phase I Proposal 2653 successfully submitted. Receipt: # 2653-1 Changed te FP-POS settings as suggested. -1436431928 ----- Attempting Submission 1 (Tue Jan 18 21:08:10 GMT 2022) ----- HST Phase II Proposal 16905 successfully submitted. Receipt: # 16905-1 ----- Attempting Submission 2 (Tue Jan 18 22:57:48 GMT 2022) ----- From Swift monitoring of the X-ray hardness variability of a sample of Seyfert-1 active galactic nuclei (AGN), we have found a transient X-ray obscuration event in Mrk 841. This event was found on 2021-12-26 and confirmed again on 2022-01-02. We propose one non-disruptive HST/COS observation (1 orbit) to investigate the crucial association between the X-ray obscuration and the outflowing winds in AGN by high-resolution UV spectroscopy. Such obscuring outflows are remarkably different from the commonly-seen ionized outflows in AGN and can have important implications for the surrounding gas and the launching of AGN outflows. X-ray obscuration events have been captured with HST in only a few AGN so far, yet the scientific yield has been immense. However, there are still outstanding questions, which require further investigation of these events in additional AGN. This rare opportunity would help us in addressing the existing questions on obscuring outflows and broaden our understanding of the transient obscuration events in AGN. From recent Swift monitoring of the hardness ratio in Mrk 841 we have found a 'transient obscuration event'. The 1-orbit observation with HST/COS G130M and G160M enables us to study all the key absorption lines associated to this event. Using the UV flux information of Mrk 841 (described in the proposal) in the Exposure Time Calculator (ETC), we find that for a 1-orbit observation with the G130M/1222 and G160M/1600 gratings we obtain a S/N of about 9 at 1223 A and a S/N of about 10 at 1623 A. These S/N per resolution element is adequate to measure the broad UV absorption lines, as well as the weak, low-ionization lines associated with the new ionization state of the warm absorber. Also, for intrinsic absorption lines with widths of > 100 km/s , the spectrum can be binned to achieve S/N ratios of 15-20. Following the Phase II Proposal instructions and the allowed COS settings for Cycle 29, the central wavelengths and FPPOS positions that we have selected provide the optimum full spectral coverage of the interested regions with the G130M and G160M gratings, and maximize the potential of the detection of the relevant broad and narrow absorption lines. This enables us to fully explore the UV spectral signatures of the obscuring outflow in Mrk 841. This is a ToO proposal, so ask that the observation to be taken as soon as possible. For the BUFFER-TIME, we obtained the recommended buffer (2/3 of the buffer fill time) from the ETC for each exposure. There are no bright field objects that would prove an overlight risk to COS. Reduced gyro operations would approximately halve the opportunities for coordination with Chandra. Also, any orientation limitation would not impact our program. Because we are using two different CENWAVES with each grating and two FP-POS positions in each, we already accomplish the actual objectives of switching between different FP-POS settings: (1) Better science return: the spectrum is placed at four different locations on the detector, enabling us to detect and reject detector anomalies like dead spots, hot spots, grid-wire shadows, etc. (2) Spread the flux across the detector in multiple locations, especially in bright emission lines, to decrease charge depletion and extend the lifetime of the detectors. We do not want to sacrifice S/N with unnecessary extra exposures and increased overhead during each visit by using all 4 FP-POS settings with each CENWAVE. When only one CENWAVE is used, then 4 FP-POS settings makes sense, but that's not the case for our observations. Our chosen FP-POS settings reflect our S/N requirements while still meeting the objectives of using different FP-POS settings in our program. The PI (Dr. Missagh Mehdipour) and Co-Is have extensive experience and expertise in study of AGN outflows and analyzing and modeling data from HST, XMM-Newton, NuSTAR, Swift, and Chandra. Data from our previous X-ray and UV campaigns, and successful ToO programs, have been extensively published: - Mrk 509 campaign with 16 refereed publications - NGC 5548 campaign with 9 refereed publications - NGC 7469 campaign with 6 refereed publications - NGC 3783 ToO programme with 5 refereed publications - NGC 3227 ToO programme with 2 refereed publications (1 submitted) Some of our publications directly related to the science case of the HST/COS proposal are: Mehdipour et al. 2015, A&A, 575, A22 Mehdipour et al. 2016, A&A, 588, A139 Mehdipour et al. 2017, A&A, 607, A28 Mehdipour et al. 2021 A&A, 652, 150 Mehdipour et al. 2022 ApJ, in press, arXiv:2112.06297 Kaastra et al. 2014, Science, 345, 64 Kriss et al. 2019, A&A, 621, A12 Mao et al. 2019, A&A, 621, A99 Dr. Mehdipour has expertise in X-ray/UV spectroscopy of ionized outflows in AGN, optical-UV-X-ray continuum modelling, and photoionisation modelling. He has previously led projects on the studies of ionized outflows in AGN with Chandra, XMM-Newton, and Swift. He is the PI of successful Swift proposals targeting a sample of AGN that has included triggers for NGC 3783 and NGC 3227. Dr. Mehdipour will carry out the main analysis and modeling of the HST/COS spectrum. Dr. Kriss is an expert in multi-wavelength observations of AGN. He has vast experience in HST analysis and modelling of UV absorption lines of different types of AGN outflows. Dr. Kriss will provide advice on the analysis and modeling of the HST/COS spectrum. Prof. Kaastra is the lead developer of the SPEX code, which is used for X-ray spectroscopy and photoionisation modelling. Prof. Kaastra has experience and expertise in the X-ray studies of AGN outflows. He led the discovery of the obscuring wind in NGC 5548 with a multi-wavelength campaign using XMM-Newton, NuSTAR, Chandra, Swift, and HST in 2013-2014. Prof. Kaastra will contribute to photoionisation modelling of the new observation. Dr. Mao is an expert in high-resolution X-ray spectroscopy of AGN using XMM-Newton and Chandra. He is the PI of an awarded Chandra Cycle 22 proposal targeting obscuration in MR 2251-178. Dr. Mao will contribute to the analysis of X-ray data. Supermassive Black Holes and Active Galaxies 0 false SUPPORTED GALAXY ACCRETION DISK BLR SEYFERT WIND NO This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 COS/FUV Spectroscopic No No G130M 1222 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G160M 1600 COS/FUV Spectroscopic No No G160M 1623 1642546570075 The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. 1643739857000 286.9301021114423 (Tic-Visit :proposal-id 16905 :visit-id "01" :proposal-version -1 :trans-version "20210514" :date "18-Jan-2022 17:56:09.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 87360 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16905 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16905 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2534 :al-overhead-at-end 0 :internal-dur-at-end 334 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2927 :pcs-gap 0 ) true 1 0 Using the UV flux information of Mrk 841, and its range, the exposure calculated with ETC provides a S/N of 30. S/N of about 9 at 1223 A S/N of about 9 at 1223 A S/N of about 9 at 1223 A S/N of about 9 at 1223 A S/N of about 10 at 1623 A S/N of about 10 at 1623 A S/N of about 10 at 1623 A S/N of about 10 at 1623 A