16417( 2) - 20-Jul-2020 14:59:24 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16417 Version: 2 Check-in Time: 20-Jul-2020 14:59:24 STScI Edit Number: 0 Title Constraining the threshold luminosity limit for broad line production in AGN ------------------------------------------------------------------------------------ Type Cycle GO/DD 27 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Marianne Vestergaard University of Copenhagen, Niels Bohr Y Institute CoI: Dr. Sandra Raimundo University of Copenhagen, Niels Bohr N Institute CoI: Prof. Bradley M Peterson The Ohio State University N CoI: Dr. Gisella De Rosa Space Telescope Science Institute N CoI: Daniel P. Lawther University of Copenhagen, Niels Bohr N Institute CoI: Dr. Jun Yi (Kevin) Koay Academia Sinica, Institute of Astronomy N and Astrophysics ------------------------------------------------------------------------------------ Abstract Mrk 590 is a changing-look AGN that is currently in an unusual low flux state, after several years of flaring. This offers a very rare opportunity to constrain the unknown threshold ionizing luminosity required for production of broad emission lines in AGN, something that is very difficult to do unless the target and conditions are just right. Given the stochastic nature of black hole accretion and the past history of strong flares this program cannot wait for the next Cycle. We propose to obtain a 1-orbit COS spectrum of Mrk 590 now (non-disruptive, within the normal ~3 week turn around time scale) to test for the presence of broad UV emission lines. We will measure UV broad-line fluxes (or upper limits) and constrain the UV-EUV continuum emission from the accretion disk. By combining these measurements and previous observations of this target we will constrain the threshold ionizing luminosity required for broad-line production. This allows us to test existing theoretical models of broad line production. This HST program is part of a larger ongoing campaign with Swift, NuSTAR, XMM and VLT to provide a comprehensive account of the accretion state changes during the early onset of AGN activity as the AGN builds up. These HST/COS data will contribute with unique information to the legacy database on this intriguing object that will undoubtedly spawn new insight on AGN physics and the changing-look AGN phenomenon. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose to obtain COS low resolution FUV observations of the Seyfert 1 galaxy Mrk 590 to determine if the AGN thermal emission and broad emission lines are present at the current X-ray level as detected by Swift. Using the G140L grating @1105 Ang we will be able to cover the Lya1215, NV1240, Si IV + O IV1400, C IV1549, HeII1640 and CIII]1909 broad emission lines in a single 16417( 2) - 20-Jul-2020 14:59:24 - [ 2] exposure. The grating resolution is adequate to resolve the typical AGN narrow emission components; the width of the [O III]5007 narrow line is FWHM~400 km s-1. As explained in the Phase I, the target has been closely monitored with SWIFT. The latest UVW2 flux (centroid wavelength 1928), obtained on July 15th 2020, is equal to ~2.4e-15 erg s-1 cm-2 Ang-1. Note: the target has already been successfully observed in the same configurations during faint state (PID 13518) ACQUISITION: The target has precise 2MASS coordinates (ICRS reproduced with an error < 0.1"). We plan to use ACQ/IMG NUV MIRRORB and an exp time of 70 s. For our ETC calculations we assume a flat continuum in f_l normalized to the min observed UVW2 flux since 2014 f_l ~6.5e-16 erg s-1 cm-2 Ang-1 @1928 Ang (http://etc.stsci.edu/etc/results/COS.ta.1456009/). This will ensure acquisition in case of "faint" state. The source will not pose a threat to the detector even if it ends up being 2 times more luminous than the max detected in the past 10 years f_l ~8.4e-15 erg s-1 cm-2 Ang-1 @1928 Ang (http://etc.stsci.edu/etc/results/COS.ta.1456018/). SCIENCE: We use the G140L grating at 1105Ang with FP_POS=ALL. For ETC calculations we assume a QSO FOS template, redshifted to z=0.02609 and normalized to the observed UVW2 flux in July 2020 (http://etc.stsci.edu/etc/results/COS.sp.1456015/). Buffer time is set to 2/3 of the ETC buffer time. The source will not pose a threat to the detector even if it ends up being 2 times more luminous than the max detected in the past 10 years f_l ~8.4e-15 erg s-1 cm-2 Ang-1 @1928 Ang (http://etc.stsci.edu/etc/results/COS.sp.1456016/). ------------------------------------------------------------------------------------ 16417( 2) - 20-Jul-2020 14:59:24 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC-863 GALAXY, ACCRETION DISK, RA=02H14M33.5790S +/- 0.1", J2000 V = 13.81 AGN V-band magnitude is BLR, NUCLEUS, SEYFERT DEC=-00D46'0.28" +/- 0.1" currently 14.8mag Reference Frame: ICRS Extended: NO Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 16417( 2) - 20-Jul-2020 14:59:24 - [ 4] Visit: 01 (Visit 01 - Mrk 590) Visit Requirements: On Hold Comments: Additional Comments: COS FUV spectrum Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC-863 COS/NUV ACQ/IMA PSA MIRRORB 1 70 S (70 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC-863 COS/FUV TIME-TA PSA G140L 1105 FP-POS=ALL, BUFFER-TIME=3900 1 474 S G see below (1940 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGC-863 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE NGC-863 2 COS/FUV TIME-TA PSA G140L 1105 none none none 1 1 485.0 S G NGC-863 2 COS/FUV TIME-TA PSA G140L 1105 none none none 2 1 485.0 S G NGC-863 2 COS/FUV TIME-TA PSA G140L 1105 none none none 3 1 485.0 S G NGC-863 2 COS/FUV TIME-TA PSA G140L 1105 none none none 4 1 485.0 S G 16417( 2) - 20-Jul-2020 14:59:24 - [ 5] Summary Form for Proposal 16417 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=3900, FP-POS=ALL ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC-863 ------------------------------------------------------------------------------------------------------------------------------------