16433( 3) - 24-Sep-2020 13:26:57 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16433 Version: 3 Check-in Time: 24-Sep-2020 13:26:57 STScI Edit Number: 1 Title Has the UV broad line region around the black hole in Mrk 279 been disrupted? ------------------------------------------------------------------------------------ Type Cycle GO/DD 27 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Edward M. Cackett Wayne State University Y CoI: Dr. Jon Matthew Miller University of Michigan N CoI: Dr. Gerard A. Kriss Space Telescope Science Institute N CoI: Dr. Elisa Costantini Space Research Organization Netherlands N CoI: Dr. Elias Kammoun University of Michigan N CoI: Dr. Abderahmen Zoghbi University of Michigan N ------------------------------------------------------------------------------------ Abstract A recent X-ray spectrum of the Seyfert 1.5 Mrk 279 shows a remarkable, unprecedented change - a previously strong narrow Fe K line has disappeared. The X-ray continuum spectrum is otherwise normal in brightness and shape. If the narrow line is formed at distances of ~1 pc, around the obscuring torus, it is difficult for the flux to disappear from such an extended structure, either via obscuration or photoionization changes. This suggests that the line may be formed in the broad line region. However, recent ground-based optical spectra show that the broad Balmer lines have normal widths and intensity. The accretion flow must have changed dramatically at smaller radii, potentially signaling a torn or disrupted disk. Clues to such a disruption could be apparent in the shape of the UV/optical continuum or the structure of the inner parts of the BLR. To test this possibility, we propose to obtain a UV through optical spectrum to examine the continuum shape and to probe the high-ionization UV broad lines (Ly alpha, NV, C IV, He II) which are formed 2-10 times closer to the central engine than the Balmer lines. ------------------------------------------------------------------------------------ Observations Description ------------------------ The narrow Fe K emission line in the Seyfert galaxy Mrk 279 has recently disappeared in X-ray spectra obtained with NuSTAR. We will obtain spectra with a S/N of ~15 covering the wavelength range from the far-UV to the optical, encompassing the major broad lines visible in a typical AGN spectrum: Ly alpha, N V 1240, Si IV 1400, C IV 1550, He II 1640, C III] 1909, Mg II 2798, H beta, and [O III] 4959, 5007. We will acquire the target using an imaging target acq with the STIS CCD in the long-pass filter. Using the gratings G430L (with the CCD), G140L (FUV MAMA) and G230L (NUV MAMA), we will cover the full wavelength range. Current ground-based observations show a continuum flux level near H beta at 4900 A of 1e-15 erg/cm2/s/A. Our calculations using the STIS ETC use the SDSS-based QSO spectrum as a model, z=0.03045, and E(B-V)=0.014. All observations fit in a single orbit. Bright object checking shows a violation with GSC2, but this is due to the host galaxy, which is extended and has an integrated brightness of V=10.4. GALEX shows that the nucleus and surrounding field are safe for STIS. ------------------------------------------------------------------------------------ 16433( 3) - 24-Sep-2020 13:26:57 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 MRK-279 GALAXY, ACCRETION DISK, RA=13H53M3.4351S, J2000 V = 14.46 5.5E-15 erg/cm^2/s/A at 2246A BLR, NLR, NUCLEUS, DEC=+69D18'29.41" from recent Swift/UVM2 observations SEYFERT Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2015.5 -3.735763090644583E-5 -8.600004548497964E-5 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 16433( 3) - 24-Sep-2020 13:26:57 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.2 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 16433( 3) - 24-Sep-2020 13:26:57 - [ 4] Visit: 01 Visit Requirements: SCHED 100% On Hold Comments: Additional Comments: 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 MRK-279 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 5 S (5 S) Comments: In case the target is fainter than expected, we use a 5 s exposure instead of the 1 s exposure from the ETC calculation at the current brightnesss level of 1e-15 at 4900 A. ------------------------------------------------------------------------------------------------------------------------------------ 2 MRK-279 STIS/CCD ACCUM 52X0.2E1 G430L 4300 CR-SPLIT=NO 1 50 S (150 PATTERN 1 2 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 MRK-279 STIS/FUV ACCUM 52X0.2 G140L 1425 1 732 S (732 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 4 MRK-279 STIS/NUV ACCUM 52X0.2 G230L 2376 1 400 S (400 -MAMA 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 | ------------------------------------------------------------------------------------------------------------------------------------ MRK-279 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A MRK-279 2 STIS/CCD ACCUM 52X0.2E1 G430L 4300 1 none none none 1 N/A MRK-279 2 STIS/CCD ACCUM 52X0.2E1 G430L 4300 2 none none none 1 N/A MRK-279 2 STIS/CCD ACCUM 52X0.2E1 G430L 4300 3 none none none 1 N/A MRK-279 3 STIS/FUV ACCUM 52X0.2 G140L 1425 none none none none 1 N/A -MAMA MRK-279 4 STIS/NUV ACCUM 52X0.2 G230L 2376 none none none none 1 N/A -MAMA 16433( 3) - 24-Sep-2020 13:26:57 - [ 5] Summary Form for Proposal 16433 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.2, 52X0.2E1, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT, CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 2, SCHED 100% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, G230L, G430L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names MRK-279 ------------------------------------------------------------------------------------------------------------------------------------