1. Gas and Dust observations with OSIRIS WAC narrowband filters
Dennis Bodewits, Fiorangela LaForgia, Mike A’Hearn, Luisa Lara, Monica Lazzarin, OSIRIS gas working group

2. OSIRIS gas measurements
observations gas with narrowband filter (OI, CN, OH, ..)
contemporaneous observations continuum with nearby filter
Continuum removal factors derived from 16 Cyg AB observations
Problem: Measured fluxes in the gas filters require unrealistically high production rates (1028 molecules/s)
Acquisition
Calibration
Background Removal
Gas
Remove dust from gas
Column Densities
Production Rates
Acquisition
Calibration
Background Removal
Dust Color
Dust

3. Image Acquisition Completely saturated:
MTP6/STP12 O1-1 (F17), NH
Problem with some level 2 to level 3 conversions
Binning is now an average rather than a sum
Sequence NH/NH2 has no continuum observation
Was designed to be simultaneous with OI & CN

4. Image Processing/Calibration
Level 3 data with problems:
MTP6/STP12 O1-1 (F17), CN (F13+14)
MTP6/STP13 OH (F51+F61)
MTP6/STP15 OI (F17)
MTP7/STP17 OI (F17)
MTP8/STP19 CN (F13+F14)
MTP8/STP19 OI (F17)
MTP8/STP21 OI (F17)
MTP8/STP21 OH (F51+F61)
Binning now sums surface brightness, should average

5. GAS SEQUENCES - 1 Rh MTP STP Sequence Date Bin res (km/pix) MTP003
GAS_SEARCH_CN_001_OI_001
25/05/2014
3.99
8e6
1x1
83.7
GAS_SEARCH_OI_002
31/05/2014
3.96
6e6
59.5
MTP004
STP005
GAS_SEARCH_OI_003
09/06/2014
3.91
3e6
32.3
GAS_SEARCH_OI_004
13/06/2014
3.89
2e6
25.2
GAS_SEARCH_OI_005
14/06/2014
3.88
23.3
STP006
GROUND_BASED_CN_OI
25/06/2014
3.83
1e6
11.6
GAS_SEARCH_OI_006
28/06/2014
3.81
77 000
8.1 1
MTP005
STP007
GAS_SEARCH_CN_004_OI_007
04/07/2014
3.78
38 000
3.8
STP008
GAS_SEARCH_OI_008
11/07/2014
3.74
15 000
1.7
STP009
GAS_SEARCH_OI_009
20/07/2014
3.69
5 200
0.5
STP010
GAS_SEARCH_OI_010
25/07/2014
3.66
2 800
0.29
MTP006
STP011
GAS_SEARCH_CN_006
02/08/2014
3.62
500
50 m
GAS_SEARCH_OI_011

6. GAS SEQUENCES - 2 Rh MTP STP Sequence Date Bin res (m/pix) MTP006
GAS_CN_1 level3
10/08/2014
3.58
100
4x4 40
GAS_O1_1 ALL SATURATED!
2x2-4x4
20-40
STP013
GAS_NH_1 NH2 SATURATED!
15/08/2014
3.54
GAS_OH_1 level3
STP015
GAS_O1_2 level3
25/08/2014
3.49 53
10-20
MTP007
STP016
GAS_CN_2 level3
08/09/2014
3.40 16
LGAS_NH_2 level3
STP017
GAS_O1_3 level3
09/09/2014 29
5-11
MTP008
STP019
GAS_O1_4 level3
25/09/2014
3.30 27
GAS_CN_3 level3
STP021
GAS_O1_5 level3
GAS_OH_2 level3

7. Background: Galactic Center
2MASS Infrared 3°x3° star field
254 DN
15,000 DN
270 – 320 DN
Equatorial Coordinates:  = 270°.80 δ = -27°.18
Galactic coordinates: l = ° b = °
We are pointing in the galactic center!

8. Original Median
2D Background Cleaned Median

9. Background: unresolved stars
DSS
DSS
OI on 7/26

10. Artifacts: ghost(s)
STP16/CN

11. Continuum removal and Dust Color
Gas filters are close to dust filters
Grey dust removal factors determined from 16Cyg AB observations
Missing several filters, CR contamination
Addressed: changed filter sequence for next calibration run on 16Cyg, multiple exposures for OH and UV filters

12. 16 Cyg AB Sequence Current Exptime (s) Proposed vis 610 180 OI Na CN
Measured
16CygAB
2008
2010
2014
Filter
Number
W/m2/sr/nm
Vis610
F18
2.36E-05
2.37E-05 OI
F17
2.21E-05
2.24E-05 CN
F14 -
1.68E-05
1.65E-05
UV375
F13
1.44E-05
1.60E-05
Current
Exptime (s)
Proposed
vis 610
180 OI Na CN
360
NH2
UV375 OH
Red
100
Green
300
Calibration changes so all need to be done

13. Continuum removal and Dust Color
Gas filters are close to dust filters
Grey dust removal factors determined from 16Cyg AB observations
Missing several filters, CR contamination
Addressed: changed filter sequence for next calibration run on 16Cyg, multiple exposures for OH and UV filters
Reddening can be determined by comparing dust narrow band filters
Derived reddened continuum removal factors
Aligning continuum and gas images (Fiorangela)

14. Continuum Removal Factors
VIS/UV
OI/VIS
CN/UV
0.0%
1.65
0.936
1.17
10.0%
1.77
0.997
1.58
12.5%
1.88
0.999
1.59
15.0%
1.99
1.001
1.60
20.0%
2.22
1.005
1.62
30.0%
2.75
1.012
1.66
Percentage per 100 nm between UV375 and VIS610 filters

15. Measure flux in continuum subtracted gas image
Distant observations: integrated flux
Aperture photometry
Stacking of early images difficult due to pointing
Saturated nucleus
Background problems
Reddening of 12% per 100 nm between UV and 610
No detection of CN, surprisingly high flux in OI
Resolved Nucleus
Map of column densities
Ghost(s)

16. Radial Profiles OI
OI – Vis610
Vis610
July 25th

17. H2O OH

18. Other emission lines in filters?
OI filter (629.6 – nm)
Vis 610 ( nm)

19. Derive Column Densities
Convert fluxes into column densities: you need to know the excitation mechanism
H2O + hv  [OI]
HCN(?) + hv  CN*

20. [OI] Excitation model for Hyakutake1S 1D
Bhardwaj & Raghuram (2012)