15164( 5) - 12-Jun-2019 14:01:08 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15164 Version: 5 Check-in Time: 12-Jun-2019 14:01:08 STScI Edit Number: 1 Title Ultraviolet spectroscopy of the dust extinction in the M31 inner bulge ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Hui Dong SETI Institute Y CoI: Prof. Q. Daniel Wang University of Massachusetts - Amherst N CoI: Dr. Zhiyuan Li Nanjing University N CoI: Dr. Aigen Li University of Missouri - Columbia N CoI: Dr. Knut Anders Grova Olsen National Optical Astronomy Observatory, N AURA ------------------------------------------------------------------------------------ Abstract The extinction curve in the central 250 pc region of the M31 bulge is substantially steeper than that in the Milky Way. In addition, there is also clear evidence for a strong 2175 Angstrom extinction bump, the strength of which shows variation among different dusty clumps in the region. To better understand these important characteristics of the extinction properties and their spatial variation, we propose to use the HST/STIS, the only long-slit ultraviolet spectroscopic detector available, to observe two prominent dusty clumps. Combining with the existing photometric data, we will contrast these dusty clumps with neighboring extinction-free regions to construct their extinction curves, which will allow us to precisely measure the slope in the UV wavelength range and to tightly quantify the width and strength of the 2175 Angstrom bump. The results compared with the existing multi-wavelength data will enable us to address such questions as: 1) What causes the steep slope of the extinction curve in the M31 bulge? 2) How does the variation of the extinction curve, especially the 2175 Angstrom bump, depend on the properties and environments of the clumps? The results of this investigation should have strong implications for the dust extinction corrections for stellar light from other similar galactic spheroids. ------------------------------------------------------------------------------------ Observations Description ------------------------ We use the HST/STIS long-slit (52"x2") spectroscopy with the NUV-MAMA camera and G230L grating to observe two dusty clumps in the M31 bulge. From the photometric observations taken by the HST ACS/WFC3 and SWIFT/UVOT camera, Dong et al. 2014, ApJ, 785, 136 found that these two dusty clumps seem to have a steep extinction curve (Rv=2.4-2.5) and strong 2175 A extinction bumps, but with different strengths. Therefore, the main purpose of this program is to use the HST/STIS spectra to characterise the extinction curves of the two dusty clumps, such as Rv and the strength of the 2175 A bump. We use a nearby (~ 1 arcminute away) bright globular cluster, M31GC J004248+411537 (B=16.13, V=15.32 mag) to be the reference target. After the telescope locks the cluster through the acquisition observation, we will shift the telescope to our targets. 15164( 5) - 12-Jun-2019 14:01:08 - [ 2] Limited by the size of the NUV-MAMA camera, the length of the long-slit is accurately 25". Therefore, we use two pointing to cover the two dusty clumps, respectively. In order to make sure that we observe the same lint-of-sight, we use a continuous observations with 5 orbits for each dusty clump. 'STIS-ALONG-SLIT' pattern is used to correct the hot pixels and remove the cosmic rays. Because we extract the spectrum from 100 pixels (0.024608"/pixel in AXIS2), we shift along the grid with 2.46" for three times. ------------------------------------------------------------------------------------ 15164( 5) - 12-Jun-2019 14:01:08 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 REFERENCE-GC ISM, BULGE, MOLECULAR RA=00H42M48.0490S, J2000 V = 15.32 +/- 10 CLOUD DEC=+41D15'37.02" Reference Frame: ICRS Comments: It is a bright globular cluster in the M31 bulge near our targets. (B=16.13, V=15.32 mag) ------------------------------------------------------------------------------------------------------------------------------------ 2 M31-BULGE-CL ISM, MOLECULAR CLOUD RA-OFF=-0.0170288 D, J2000 V = 18 UMPA DEC-OFF=0.0128212D, FROM 1 ------------------------------------------------------------------------------------------------------------------------------------ 3 M31-BULGE-CL ISM, MOLECULAR CLOUD RA-OFF=-0.0231085D, J2000 V = 18 UMPB DEC-OFF=0.00750351D, FROM 1 ------------------------------------------------------------------------------------------------------------------------------------ 15164( 5) - 12-Jun-2019 14:01:08 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 2.4608 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern YES ------------------------------------------------------------------------------------------------------------------------------------ 15164( 5) - 12-Jun-2019 14:01:08 - [ 5] Visit: 01 Visit Requirements: ORIENT 263D TO 265 D; ORIENT 83D TO 85 D 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 REFERENCE-G STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 5 S (5 S) GS ACQ SCENARIO BASE1B3; C SEQ 1-2 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 M31-BULGE-C STIS/NUV ACCUM 52X2 G230L 2376 2 335 S PATTERN 1 2 LUMPA -MAMA (2010 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 M31-BULGE-C STIS/NUV ACCUM 52X2 G230L 2376 2 401 S SEQ 3 NON-INT; PATTERN 1 LUMPA -MAMA (2406 S) 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 M31-BULGE-C STIS/NUV ACCUM 52X2 G230L 2376 2 401 S SEQ 4 NON-INT; PATTERN 1 LUMPA -MAMA (2406 S) 4 ------------------------------------------------------------------------------------------------------------------------------------ 5 M31-BULGE-C STIS/NUV ACCUM 52X2 G230L 2376 2 401 S SEQ 5 NON-INT; PATTERN 1 LUMPA -MAMA (2406 S) 5 ------------------------------------------------------------------------------------------------------------------------------------ 6 M31-BULGE-C STIS/NUV ACCUM 52X2 G230L 2376 2 401 S SEQ 6 NON-INT; PATTERN 1 LUMPA -MAMA (2406 S) 6 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ REFERENCE-GC 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A M31-BULGE-CLUMPA 2 STIS/NUV ACCUM 52X2 G230L 2376 1 none 1 none 1 N/A -MAMA M31-BULGE-CLUMPA 2 STIS/NUV ACCUM 52X2 G230L 2376 1 none 2 none 1 N/A -MAMA M31-BULGE-CLUMPA 2 STIS/NUV ACCUM 52X2 G230L 2376 2 none 1 none 1 N/A -MAMA M31-BULGE-CLUMPA 2 STIS/NUV ACCUM 52X2 G230L 2376 2 none 2 none 1 N/A -MAMA M31-BULGE-CLUMPA 2 STIS/NUV ACCUM 52X2 G230L 2376 3 none 1 none 1 N/A -MAMA M31-BULGE-CLUMPA 2 STIS/NUV ACCUM 52X2 G230L 2376 3 none 2 none 1 N/A -MAMA M31-BULGE-CLUMPA 3 STIS/NUV ACCUM 52X2 G230L 2376 1 none 1 none 2 N/A -MAMA M31-BULGE-CLUMPA 3 STIS/NUV ACCUM 52X2 G230L 2376 1 none 2 none 2 N/A -MAMA 15164( 5) - 12-Jun-2019 14:01:08 - [ 6] 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 | ------------------------------------------------------------------------------------------------------------------------------------ M31-BULGE-CLUMPA 3 STIS/NUV ACCUM 52X2 G230L 2376 2 none 1 none 2 N/A -MAMA M31-BULGE-CLUMPA 3 STIS/NUV ACCUM 52X2 G230L 2376 2 none 2 none 2 N/A -MAMA M31-BULGE-CLUMPA 3 STIS/NUV ACCUM 52X2 G230L 2376 3 none 1 none 2 N/A -MAMA M31-BULGE-CLUMPA 3 STIS/NUV ACCUM 52X2 G230L 2376 3 none 2 none 2 N/A -MAMA M31-BULGE-CLUMPA 4 STIS/NUV ACCUM 52X2 G230L 2376 1 none 1 none 3 N/A -MAMA M31-BULGE-CLUMPA 4 STIS/NUV ACCUM 52X2 G230L 2376 1 none 2 none 3 N/A -MAMA M31-BULGE-CLUMPA 4 STIS/NUV ACCUM 52X2 G230L 2376 2 none 1 none 3 N/A -MAMA M31-BULGE-CLUMPA 4 STIS/NUV ACCUM 52X2 G230L 2376 2 none 2 none 3 N/A -MAMA M31-BULGE-CLUMPA 4 STIS/NUV ACCUM 52X2 G230L 2376 3 none 1 none 3 N/A -MAMA M31-BULGE-CLUMPA 4 STIS/NUV ACCUM 52X2 G230L 2376 3 none 2 none 3 N/A -MAMA M31-BULGE-CLUMPA 5 STIS/NUV ACCUM 52X2 G230L 2376 1 none 1 none 4 N/A -MAMA M31-BULGE-CLUMPA 5 STIS/NUV ACCUM 52X2 G230L 2376 1 none 2 none 4 N/A -MAMA M31-BULGE-CLUMPA 5 STIS/NUV ACCUM 52X2 G230L 2376 2 none 1 none 4 N/A -MAMA M31-BULGE-CLUMPA 5 STIS/NUV ACCUM 52X2 G230L 2376 2 none 2 none 4 N/A -MAMA M31-BULGE-CLUMPA 5 STIS/NUV ACCUM 52X2 G230L 2376 3 none 1 none 4 N/A -MAMA M31-BULGE-CLUMPA 5 STIS/NUV ACCUM 52X2 G230L 2376 3 none 2 none 4 N/A -MAMA M31-BULGE-CLUMPA 6 STIS/NUV ACCUM 52X2 G230L 2376 1 none 1 none 5 N/A -MAMA M31-BULGE-CLUMPA 6 STIS/NUV ACCUM 52X2 G230L 2376 1 none 2 none 5 N/A -MAMA M31-BULGE-CLUMPA 6 STIS/NUV ACCUM 52X2 G230L 2376 2 none 1 none 5 N/A -MAMA M31-BULGE-CLUMPA 6 STIS/NUV ACCUM 52X2 G230L 2376 2 none 2 none 5 N/A -MAMA M31-BULGE-CLUMPA 6 STIS/NUV ACCUM 52X2 G230L 2376 3 none 1 none 5 N/A -MAMA M31-BULGE-CLUMPA 6 STIS/NUV ACCUM 52X2 G230L 2376 3 none 2 none 5 N/A -MAMA 15164( 5) - 12-Jun-2019 14:01:08 - [ 7] Visit: 02 Visit Requirements: ORIENT 263D TO 265 D; ORIENT 83D TO 85 D 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 REFERENCE-G STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 5 S (5 S) GS ACQ SCENARIO BASE1B3; C SEQ 1-2 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 M31-BULGE-C STIS/NUV ACCUM 52X2 G230L 2376 2 335 S PATTERN 1 2 LUMPB -MAMA (2010 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 M31-BULGE-C STIS/NUV ACCUM 52X2 G230L 2376 2 401 S SEQ 3 NON-INT; PATTERN 1 LUMPB -MAMA (2406 S) 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 M31-BULGE-C STIS/NUV ACCUM 52X2 G230L 2376 2 401 S SEQ 4 NON-INT; PATTERN 1 LUMPB -MAMA (2406 S) 4 ------------------------------------------------------------------------------------------------------------------------------------ 5 M31-BULGE-C STIS/NUV ACCUM 52X2 G230L 2376 2 401 S SEQ 5 NON-INT; PATTERN 1 LUMPB -MAMA (2406 S) 5 ------------------------------------------------------------------------------------------------------------------------------------ 6 M31-BULGE-C STIS/NUV ACCUM 52X2 G230L 2376 2 401 S SEQ 6 NON-INT; PATTERN 1 LUMPB -MAMA (2406 S) 6 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ REFERENCE-GC 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A M31-BULGE-CLUMPB 2 STIS/NUV ACCUM 52X2 G230L 2376 1 none 1 none 1 N/A -MAMA M31-BULGE-CLUMPB 2 STIS/NUV ACCUM 52X2 G230L 2376 1 none 2 none 1 N/A -MAMA M31-BULGE-CLUMPB 2 STIS/NUV ACCUM 52X2 G230L 2376 2 none 1 none 1 N/A -MAMA M31-BULGE-CLUMPB 2 STIS/NUV ACCUM 52X2 G230L 2376 2 none 2 none 1 N/A -MAMA M31-BULGE-CLUMPB 2 STIS/NUV ACCUM 52X2 G230L 2376 3 none 1 none 1 N/A -MAMA M31-BULGE-CLUMPB 2 STIS/NUV ACCUM 52X2 G230L 2376 3 none 2 none 1 N/A -MAMA M31-BULGE-CLUMPB 3 STIS/NUV ACCUM 52X2 G230L 2376 1 none 1 none 2 N/A -MAMA M31-BULGE-CLUMPB 3 STIS/NUV ACCUM 52X2 G230L 2376 1 none 2 none 2 N/A -MAMA 15164( 5) - 12-Jun-2019 14:01:08 - [ 8] 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 | ------------------------------------------------------------------------------------------------------------------------------------ M31-BULGE-CLUMPB 3 STIS/NUV ACCUM 52X2 G230L 2376 2 none 1 none 2 N/A -MAMA M31-BULGE-CLUMPB 3 STIS/NUV ACCUM 52X2 G230L 2376 2 none 2 none 2 N/A -MAMA M31-BULGE-CLUMPB 3 STIS/NUV ACCUM 52X2 G230L 2376 3 none 1 none 2 N/A -MAMA M31-BULGE-CLUMPB 3 STIS/NUV ACCUM 52X2 G230L 2376 3 none 2 none 2 N/A -MAMA M31-BULGE-CLUMPB 4 STIS/NUV ACCUM 52X2 G230L 2376 1 none 1 none 3 N/A -MAMA M31-BULGE-CLUMPB 4 STIS/NUV ACCUM 52X2 G230L 2376 1 none 2 none 3 N/A -MAMA M31-BULGE-CLUMPB 4 STIS/NUV ACCUM 52X2 G230L 2376 2 none 1 none 3 N/A -MAMA M31-BULGE-CLUMPB 4 STIS/NUV ACCUM 52X2 G230L 2376 2 none 2 none 3 N/A -MAMA M31-BULGE-CLUMPB 4 STIS/NUV ACCUM 52X2 G230L 2376 3 none 1 none 3 N/A -MAMA M31-BULGE-CLUMPB 4 STIS/NUV ACCUM 52X2 G230L 2376 3 none 2 none 3 N/A -MAMA M31-BULGE-CLUMPB 5 STIS/NUV ACCUM 52X2 G230L 2376 1 none 1 none 4 N/A -MAMA M31-BULGE-CLUMPB 5 STIS/NUV ACCUM 52X2 G230L 2376 1 none 2 none 4 N/A -MAMA M31-BULGE-CLUMPB 5 STIS/NUV ACCUM 52X2 G230L 2376 2 none 1 none 4 N/A -MAMA M31-BULGE-CLUMPB 5 STIS/NUV ACCUM 52X2 G230L 2376 2 none 2 none 4 N/A -MAMA M31-BULGE-CLUMPB 5 STIS/NUV ACCUM 52X2 G230L 2376 3 none 1 none 4 N/A -MAMA M31-BULGE-CLUMPB 5 STIS/NUV ACCUM 52X2 G230L 2376 3 none 2 none 4 N/A -MAMA M31-BULGE-CLUMPB 6 STIS/NUV ACCUM 52X2 G230L 2376 1 none 1 none 5 N/A -MAMA M31-BULGE-CLUMPB 6 STIS/NUV ACCUM 52X2 G230L 2376 1 none 2 none 5 N/A -MAMA M31-BULGE-CLUMPB 6 STIS/NUV ACCUM 52X2 G230L 2376 2 none 1 none 5 N/A -MAMA M31-BULGE-CLUMPB 6 STIS/NUV ACCUM 52X2 G230L 2376 2 none 2 none 5 N/A -MAMA M31-BULGE-CLUMPB 6 STIS/NUV ACCUM 52X2 G230L 2376 3 none 1 none 5 N/A -MAMA M31-BULGE-CLUMPB 6 STIS/NUV ACCUM 52X2 G230L 2376 3 none 2 none 5 N/A -MAMA 15164( 5) - 12-Jun-2019 14:01:08 - [ 9] Summary Form for Proposal 15164 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X2, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GS ACQ SCENARIO BASE1B3, ORIENT 263D TO 265 D, ORIENT 83D TO 85 D, PATTERN 1 2, PATTERN 1 3, PATTERN 1 4, PATTERN 1 5, PATTERN 1 6, SEQ 1-2 NON-INT, SEQ 3 NON-INT, SEQ 4 NON-INT, SEQ 5 NON-INT, SEQ 6 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G230L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names M31-BULGE-CLUMPA, M31-BULGE-CLUMPB, REFERENCE-GC ------------------------------------------------------------------------------------------------------------------------------------