HETG

Follow-on Science Instrument

Contract NAS8-01129

Monthly Status Report Numbers 018

August 2003

Science Theme: Supernova Remnants II

Prepared in accordance with DR 972MA-002; DPD #972

Prepared for

National Aeronautics and Space Administration

Marshall Space Flight Center, Alabama 35812

 

Center for Space Research; Massachusetts Institute of Technology; Cambridge, MA 02139

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1.0 Distribution List for Monthly Status Report

 

 

MIT-External Electronic:

FD03/Mike Smith, MSFC                   Carl.M.Smith@msfc.nasa.gov

PS41/Steve Morris, MSFC                 Steven.D.Morris@msfc.nasa.gov

SD50/Martin Weisskopf, MSFC            martin.weisskopf@msfc.nasa.gov

 

MIT-External Hardcopy:

                                    None specified.

 

 

            MIT-Internal Electronic:

                                                Elaine Tirrell                egt@mit.edu

                                                Gail Monahan              gmonahan@mit.edu

 

MIT-Internal Hardcopy:

                                                Claude Canizares         Room 3-234 (via Gail Monahan)

                                                Deepto Chakrabarty     Room 37-501 (via Elaine Tirrell)

                                                Kathryn Flanagan        Room NE80-6103 (via Elaine Tirrell)

                                                File                              (via Elaine Tirrell)

 

 

Please send distribution requests and other comments on this document to dd@mit.edu .

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2.0 Schedule of Past and Future Events Relevant to HETG

 

 

Date	Past Events	Comment
Aug. 11	Abstracts due for Four Years w/Chandra , Huntsville, AL
Aug. 19	Chandra Quarterly Review
Aug. 23	SIRTF Launch

 

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3.0 Instrument Status and Science Support

 

 

3.1 Flight Events and HETG Instrument Status

 

The HETG continues to function with no outstanding issues.

In August there were 6 HETG observation intervals for 6 targets. These were all GO observations and included 3 with MIT-based PI-s: VW Cep (Dave Huenemoerder), Her X-1 (Mario Jimenez-Garate) and 4U 1822 (Prof. Chakrabarty). The data from these 3 indicate the instrument is performing nominally.

 

3.2 Science Support to CXC, SWG, etc.

 

Submitted abstract for “Four Years of Chandra Observations” symposium.

 

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4.0 GTO Science Program

4.1 Observations and Data status

Progress in our GTO program is summarized in the table of Appendix A.

 

4.2 Science theme progress

 

The HETG GTO science efforts span a range of “science themes” given in the list below. This month we present an update on the status of the Supernova Remnant GTO observations in the following pages.

 

GTO Science Theme	Abbreviation (for App’ix A)	Researchers (HETG in caps)	Date of recent [previous] reporting Assembler of theme material
“Cool” Stars	Cool Star	dph,nss,psw,bb	September, 2002. Dave Huenemoerder
“Hot” Stars	Hot Star	nss,dph,psw,bi	October, 2002. Norbert Schulz
X-ray Binaries & Accretion Disks	XRB	MJ-G,AJ,nss,hlm, man, jmm, psw	December, 2002. Norbert Schulz, Mike Nowak
Supernova Remnants	SNR	KAF,DD, AF,jh,gea,mds	August, 2003. [May, 2003] Dan Dewey
Isolated Neutron Stars	iNS	hlm, nss	January, 2003. Mike Stage, Herman Marshall
Galaxies & Clusters of Galaxies	Gal., Clust.	TJ,mw,jh	August, 2002. Michael Wise, Tesla Jeltema
Active Galactic Nuclei and Jets	AGN, Jet	RG,MJ-G,hlm, man,jcl,sm,jg	June, 2002. Herman Marshall
Inter-Stellar Medium	ISM	AJ,nss	February, 2003. Adrienne Juett, Norbert Schulz
Inter-Galactic Medium	IGM	RG,hlm	July, 2002. Taotao Fang

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Supernova Remnant Progress, Part II (June’02 – August’03)

 

Summary of Supernova Remnant Observations and Activities

In the last 14 months progress has continued in the analysis and understanding of our GTO observations of Supernova Remnants. A major accomplishment was the recent submittal to Astrophysical Journal of a comprehensive paper on E0102: “Chandra High-Resolution X-Ray Spectrum of Supernova Remnant 1E0102.2-7219” by Flanagan et al. A contribution to the High Resolution Spectroscopy workshop, “Extended Source Analysis for Grating Spectrometers” by D. Dewey (available online), summarized some techniques and results for HETG SNR analysis. The determination of masses and abundances was a focus this period and has lead to an understanding of the importance of spectral model assumptions and geometry assumptions in these calculations. The Table below lists our SNR GTO observations and for reference the other 5 known “Oxygen-rich” remnants as well; these 5 have all been observed with ACIS and no grating. Specific progress is described in the following pages.

Obs Cycle	HETGS Obsid(s)	Exp. Time (ks)	SNR Name	Loc., Dist. (kpc)	Ang. Dia.	Dia. (pc)	Age (y)	Comments
2	1045, 2410, 2416	117	N103B	LMC, 50	31”	7.5	1,500	Strong Si and Fe lines. Type 1a or Core collapse?
								Oxygen-rich SNRs w/HETGS:
2	1046	70	Cas A	Gal., 3.4	340”	5.6	320
1	121, 1828	100	N132D	LMC, 50	115”	27.9	1,350	Bright Filaments, “O blob”
1, 4	120, 968 3828	137 138	E0102	SMC, 60	44”	12.8	1,000	Weak Fe lines 90 deg roll from Cycle 1 obs.
								Other Known O-rich SNRs:
			Puppis A	Gal., 2.0	3300”	32.0	~ 5,000
			G292.0+1.8	Gal., 4.8	540”	12.5	< 1,600
			B0540-69	LMC, 50	68”	16.5	~ 1,700	PWN; 8” dia. O III ring.
			0103-72.6	SMC, 60	170”	49.4	~20,000	Older version of E0102 ? Park et al. Astro-ph/0309271
			NGC 4449	3900	<0.03”	< 0.6	~ 100	Patnaude and Fesen, ApJ 2003

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E0102

We have devoted quite a bit of energy to analysing and understanding SNR E0102 during the past year or so. During this time a comprehensive paper was completed and submitted to ApJ and includes a range of our initial results and more recently estimates of the mass of the Oxygen and Neon in the ejecta and a discussion of possible mechanisms to produce an axial/cylinderical symmetry of the remnant. Look for Flanagan et al 2003 in ApJ very soon!

 

Research extending beyond the paper has been on-going and some items are described here below.

 

 

A second E0102 HETGS observation, obsid 3828, was taken in December 2002 at a roll 90 degress from the earlier data; the MEG m=-1 order image is shown above. This 135 ks exposure has equal or greater counts than the earlier obsid 120 data (87 ks) and simultaneous analysis of them is planned especially for the Oxygen lines (red above.)

 

Count rate ratios of these Oxygen lines do show the effect of the ACIS contamination layer and their quantitative values provide support for the External Cal Source measured absorption model – indicating that there is some small additional absorption not currently in the edges-only derived model.

 

A first look spatial-spectral analysis of these new E0102 data give a spatial-velocity image for the Ne X line at right very similar to that derived from obsid 120; this inspite of the 90 degree rotation is a good confirmation of the reality of the result.

 

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The HETGS data for E0102 can be roughly fit by a single, global vnpshock model, above, which allows relative abundances of the elements to be determined under this model assumption. In the plot at right, these abundances (red) are compared with expectations from SNR models, specifically Core-collapse models (purple) and Type Ia models (green); for reference SMC/ISM abundances are also shown (blue.) As expected E0102 is unambiguously a core-collapse remnant from a progenitor of ~30 solar masses.

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Using Chandra’s high spatial resolution we have started to study localized regions of the E0102 ejecta ring, specifically the Northern “shelf” and Southeast “arc” bright features. The plots below show contours in temperature-tau model space for Oxygen line ratios from these regions. Although not identical, the similarity of temp and tau for ejecta in these two regions is a little puzzling given other indications of overall temperature and tau differences between north and sourth parts of the remnant, e.g. the intensity of flux above 2keV shown at left. These results therefore add constraints on the overall 3D model of the ejecta-plus-blastwave that we hope to create, see “3D Modeling” section below. (Plots from Fredericks et al., poster at 201^st AAS meeting.)

 

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N132D

One item of note in N132D analysis is the overplotting of the grid of shock model predictions on the ratio-ratio plot shown above. The ratio of O VIII Lyman alpha to total O VII triplet (r+I+f) flux is plotted on the X-axis. The Y-axis gives the O VII forbidden to resonance ratio. Values of these ratios for a variety of features/filaments in N132D are plotted by red symbols. The overlayed grid shows the region spanned by the model for various T and tau values. The NE-corner region has an unexpectedly high f/r ratio. The raw data for NE-corner are shown at right with the model fit and decomposition into the r, i, and f contributions; the bottom panel shows the nominal feature profile and specific region of interest. (Plots from Fredericks et al., Poster at Con-X meeting, May 2003.)

 

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N103B

 

We fit the global HETGS spectrum of N103B with a model, shown above left, that is the sum of high-T (green) and low-T (red) “vnpshock”s with variable abundances plus a small synchrotron “srcut” component (blue.) The total spectrum agrees well with our data.

The plot in the upper right shows the contribution of Fe emission (green) to a shock model (other elements’ emission shown in grey.) The “Iron forest” between 7A and 18A is a major contributor to the N103B model in that range making it hard to clearly identify Ne and Mg emission in that range.

Shown at right are the abundances from the 2T model (red) compared with Ia and core-collapse models (green, purple) and the LMC ISM abundance (blue dotted.) Our model abundance ratios are tantalizingly in between the Ia and core-collapse predictions; mass estimates are ongoing. (From M.S. Thesis by J. Migliazzo, 2003.)

 

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3D Modeling

 

1:, 2:, 3:, 4:.

 

The red-green spatial-velocity image of derived for the Ne X line in E0102 suggests a cylinderical ejecta distribution, 1 above, viewed nearly on-axis. In order to qualitatively and quantitatively test this and related ideas on E0102’s structure we’ve started to explore the creation of 3D plasma models and their X-ray emission. As an example 2 above, shows the X-ray color-coded intensity image cylinderical ejecta surrounded by a spherical blastwave shell.

We’re also looking at available 3D software and how it could be used in 3D astrophysical modeling. For example, 3 above, shows a view from the modeling window of the Blender software in which a cylinder (green mesh), an observer (pink) and light source (yellow dot) have been defined. When this model is “rendered” the image shown in 4 above is generated. Ideally the same model definition software could be used as input to an “X-ray renderer” for X-ray modeling.

 

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Supernova Remnant Plans, Part II

 

Our plans for the next year or so are given here. A general additional topic for all of our SNR research would be to include and understand obseravtions made at other wavelengths like radio, optical and IR.

 

E0102

·      Compare fluxes with models, e.g., power-law shock model values.

·      Investigate 3-D models for their agreement with the Ne X spatial-velocity results and the variation of ionization stage with position.

·      Create s/w to jointly analyze the Cycle 1 and Cycle 4 E0102 observations, especially for O VIII, O VII lines.

 

N132D

·      Try including an Fe "pseudo continuum" to better measure Ne and Mg line fluxes in the various regions.

·      Understand the enhanced O forbidden emission in the NE-corner region.

·      Find the abundance ratios for a global fit to a single vnpshock model, compare w/Ia,II yields.

 

N103B

·      Complete Paper 1 on N013B.

·      Carry out spatial-spectral analysis of Si lines by combining MEG and HEG data sets.

 

Cas A

·      For the Si feature combine grating line flux values with ACIS zeroth-order continuum values to get n_H/n_Si and feature masses.

·      Analyze additional features in Si and S for flux, temp, mass, and doppler velocities.

·      Find the abundance ratios for a global fit to a single vnpshock model, compare w/Ia,II yields.

 

Advanced Analysis

·      Investigate use of 3D s/w and tools for SNR modeling, specifically for E0102 modeling.

·      Work with ISIS s/w team to determine useful spatial-spectral s/w functions to be added to ISIS.

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4.3 HETG-related Software: Development, Evaluation, and Support

 

Software created for the SNR analyses described here include: a combined random-search/fitting method was used in ISIS to find good fits of the vnpshock model to E0102 and N103B data sets; the procedure rr_grid.pro was written to overplot model grids on the ratio-ratio plots (N132D); and a set of IDL routines (“v3d_….pro”)were written to do some simple 3D modeling and visualization.

4.4 Presentations, etc. (August)

 

 

A quiet month for talks.

 

 

 

4.5 Publications (August), see also: http://space.mit.edu/csr_pubs.html

 

K.A. Flanagan, C.R. Canizares, D. Dewey, J.C. Houck, A.C. Fredericks, M.L. Schattenburg, T.H. Markert, D.S. Davis, “Chandra High-Resolution X-Ray Spectrum of Supernova Remnant 1E0102.2-7219”, ApJ submitted.

Adrienne M. Juett & Deepto Chakrabarty, “X-ray Spectroscopy of the Low-Mass X-ray Binaries 2S 0918-549 and 4U 1543-624”, ApJ accepted, Vol. 599 (2003.)

Herman L. Marshall, Daniel Dewey, and Kazunori Ishibashi, “In-Flight Calibration of the Chandra High Energy Transmission Grating Spectrometer”, SPIE Volume 5165 (2003.)

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5.0 Systems and Engineering Support

 

5.1 Documentation and “Design Knowledge Capture” and 5.3 Anomalies, Insert/retract, etc. Support

5.2 Spares Retest and Test Instrumentation

 

No activities in these areas in August.

 

6.0 Management

 

6.1 Program Office & NASA Support

 

Supported the Chandra Quarterly Review on 8/19.

 

6.2 MIT-internal management activities

 

Arranged/initiated phone and room changes for September personnel changes.

 

 

7.0 Open Issues, Problems, etc.

 

There are no open issues or problems regarding the HETG.

 

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Appendix A. HETG GTO Observation Status Tables

 

Notes:

1.    Entries indicating progress during this period are shown in this font.

2.    For CSR Publication references (CSR-YY-NN) see http://space.mit.edu/csr_pubs.html

3.    Up-to-date observation information can be obtained from http://cxc.harvard.edu/cda/ using WebChaSeR ; this archive page also has a link to the ADS which allows searching for papers by Chandra obsid.

 

Cycle 5

Object Science Theme	AO	Obs ID	Seq. No.	Expos. (ks)	Observer / Analyst	Start Date	Comments & Analysis	Talks and Publications
4U 1957+11 XRB	5	TBD	Prop. 05400034	[67]	M. Nowak	[TBD]	Target accepted in peer review.
MCG—6-30-15 AGN	5	TBD	Prop. 05700032	[540 ! ]	J. Lee	[TBD]
Orion Nebula Cluster “Hot” Stars	5	TBD	Prop. 05200040	[100.0]	N. Schulz	[TBD]

 

 

Cycle 4

Object Science Theme	AO	Obs ID	Seq. No.	Expos. (ks)	Observer / Analyst	Start Date	Comments & Analysis	Talks and Publications
4U 1626-67 XRB	4	3504	400257	97.1	N. Schulz	6/5/03	XMM obs on 8/20. Spectra analyzed[7,8/03]. Data in-house, spectra good[6/03]. (Cycle 1 obs. also)
Sco X-1 XRB	4	3505	400258	16.1	N. Schulz	7/21/03	CC Data being processed [7/03]. Multi-wavelength obs organized[1/03].
H1426+428 IGM	4	3568	700630	101.0	T. Fang	9/8/03	Prop. No.: 04700987
Mrk 290 AGN	4	3567 4399 4441 4442	700629	55 85 61 50	J. Lee	6/29/03 7/15/03 7/15/03 7/17/03	Replanning FUSE obs.[8/03] Data in-house [6,7/03]. FUSE proposal submitted for coord. Obs[1/03].
TV Crit “Cool” Stars	4	3728