HETG

Follow-on Science Instrument

Contract NAS8-01129

Monthly Status Report Number 022

December 2003

Science Theme: X-Ray Binaries, Part 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

 

1.0 Distribution List for Monthly Status Report

 

 

MIT-External Electronic:

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

PS41/Wayne Harmon, MSFC                 Wayne.T.Harmon@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 .

 

2.0 Schedule of Past and Future Events Relevant to HETG

 

Date

Past Events

Comment

Dec. 8-12

Multiwavelength AGN Surveys, Cozumel, Mexico

M. Jimenez-Garate, J. Gelbord

Dec.15

Chandra Cycle 6 Call for Proposals issued

 

Jan. 4-8

203rd AAS meeting, Atlanta GA.

Flanagan, Ishibashi, Marshall, Gelbord, Porro, Jimenez-Garate, Wise, Lopez, Wojdowski, Jeltema, Juett

Jan. 12

Chandra User Committee meeting

 

 

 

Date

Future Events

Comment

Jan. 15-16

Studies of Dark Energy & Cosmology with X-ray Surveys, Greenbelt, MD.

 

Feb. 3-6

“X-ray and Radio Connection”, Sante Fe, NM.

J. Houck, G. Allen

Feb. 8-12

Polarimetry meeting, Stanford U., CA.

H. Marshall

March 1

GTO target selections due to CXC

 

March 3-4

Chandra Quarterly at MSFC

D. Dewey

May

Wyoming meeting

B. Ishibashi

May 12-14

Conference: "Beyond Einstein: From the Big Bang to Black Holes", Kavli Institute, Stanford U., CA..

K. Flanagan

May 18-24

5th Microquasar Workshop, Beijing, China

H. Marshall, S. Heinz

May 30-6/3

AAS Meeting, Denver, CO.

N. Schulz

June 21-25

Astronomical Telescopes and Inst., SPIE Meeting, Scotland.

K. Flanagan

June 20-25

Growing Black Holes: Accretion in a Cosmological Context, Garching, Germany.

H. Marshall, S. Heinz

July 5-9

13th Cambridge Workshop on Cool Stars, Hamburg Germany

N. Schulz

July 18-24

35th COSPAR meeting, Paris France.

 

C. Canizares, K. Flanagan,

H. Marshall

 

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 December 2003 there were 2 obsids using the HETG: targets Epsilon Ori and a TOO of Her X-1 (HETG PostDoc Mario Jimenez-Garate PI).

 

3.2 Science Support to CXC, SWG, etc.

 

Parameters for an improved ACIS contamination file were created and sent to CXC for creation of a CALDB product, an “N0003” version of contaminant response is the goal.

Working with CXC to create an HETG proposal planning thread for Cycle 6 use.

 

 

 

 

4.0 GTO Science Program

4.1 Observations and Data status

No new GTO data were received in December. Progress in on-going analysis is given in the GTO observation list of Appendix A --- not included this month, however.

 

4.2 Science theme progress

The HETG GTO science efforts span a range of “science themes” given in the list below. For this report we present in the following pages an update on the status of the X-Ray Binaries GTO observations.

 

GTO Science Theme

Abbreviation

(for App’ix A)

Researchers

(HETG in caps)

Date of recent [previous] reporting

Contributor of theme material

“Cool” Stars

Cool Star

dph,nss,psw

Oct.&Nov., 2003. [Sept.2002]

Dave Huenemoerder

“Hot” Stars

Hot Star

nss,dph,psw,bi

Oct.&Nov., 2003. [Oct. 2002]

N. Schulz, P. Wojdowski

X-ray Binaries & Accretion Disks

XRB

MJ-G,AY,AJ,nss,hlm,

man, jmm, psw

December, 2003 [Dec. 2002]

Many contributors.

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,AY,mw,jh

August, 2002.

Michael Wise, Tesla Jeltema

Active Galactic Nuclei and Jets

AGN, Jet

RG,MJ-G,AY,hlm,

man,jcl,sm,jg,scg

September, 2003. [June, 2002]

Andy Young and Rob Gibson

Inter-Stellar Medium

ISM

AJ,nss

February, 2003.

Adrienne Juett, Norbert Schulz

Inter-Galactic Medium

IGM

RG,hlm,tf

July, 2002.

Taotao Fang

X-Ray Binaries Progress, Part II (January ’03 – December ‘03)

 

 

Summary of X-Ray Binaries Observations and Activities

 

Eleven XRBs are included in cycles 1-5 of the HETG GTO program, covering a range of types as indicated in the Table below. In the past year the two Cycle 4 observations, 4U 1626-67 and Sco X-1, were carried out and data are being analyzed, see examples that follow. Progress has also been made in understanding photoionized emission from EXO 0748 and Her X-1, in analyzing piled-up XRB observations, and in modeling the jets of SS 433 --- this latter activity yielded a press release at the recent AAS meeting in Atlanta.

Aditionally, because many XRBs are bright continuum sources they can be used to probe the absorption details of the interstellar medium (ISM); a figure from the recent ApJ paper by Juett, Schulz, and Chakrabarty (2003) will appear in the upcoming Chandra Newsletter demonstrating the detailed Oxygen absorption due to the ISM.

 

Obs

cycle

Obsid(s)

Name

ISM?

Type*

Period

Comments

5

4552

4U 1957+11

---

LMXB: BH or NS ?

9.3 h

Warped precessing disk, 2 orbits

4, 1

3504, 104

4U 1626-67

---

LMXB: PS

42 m

Magnetic NS; ultra-compact

4

3505

Sco X-1

Yes

LMXB: NS,Z

18.9 h

Bright! Fe XXV, ADC, ISM (XAFS?)

3

3354

GX 349+2

Yes

LMXB: NS,Z

14.9 d?

ISM Fe-L and O edges

2

1016

Cyg X-2

Yes

LMXB: NS,Z

9.8 d

Bursts, super-orbital P, 0.5 Crab

2

1017

EXO 0748-676

---

LMXB: NS

3.8 h

Bursts, eclipses, dips

1, 2

1020, 1019, 106

SS 433

---

HMXB?: ?

13 d

Precessing jets, super-orbital P

1

103

GX 301-2

---

HMXB: PS

41.5 d

Eccentric orbit, wind accretion

1

102

Vela X-1

---

HMXB: PS

9 d

Winds

1

105

4U 1636-53

Yes

LMXB: NS,A

3.8 h

Bursts

1

107, 1511

Cyg X-1

Yes

HMXB: BH

5.6 d

Fe-line structure, wind

* Key: Z = Z source, A = Atoll source, PS = X-ray pulsar, NS = neutron star, BH = black hole

 

4U 1626-67 – second observation.

 

In cycle 4 we again observed the binary 4U 1626-67 (in June ’03) but this time for 2.5x as long as our earlier cycle 1 observation (Sept. ’00): 100 ks as compared with 40 ks. We have also obtained and are analyzing an XMM-Newton observation of the source taken in August ’03, see Figure below left. The emission lines are very broad and continue to show a double peak structure, for example, in the Ne X line show in the Figure below right taken from the second Chandra observation. The exact line structure of the double peaks, their location and relative intensities, appears to have changed between the two Chandra observations. Analysis of these data are on-going.

 

 

 

 

 

Sco X-1 Observed!

 

On July 21 2003 Chandra pointed at the brightest continuous X-ray source in the sky –-- Sco X-1 --- as part of the HETG GTO cycle 4 program. Because the source is so bright there was fear that if the zeroth-order image fell directly on a FI CCD damage could result; the observation was monitored in real time by operations personnel and the observation was a success. In addition ACIS was run in CC mode and offset in SIM-Z so that the zeroth-order landed off-chip so that only a single arm of each of the MEG and HEG intersected the ACIS-S array. This is a far-from-standard configuration makes the data analysis tricky. For example, the “order plot” shown in the Figure below left has HEG-only on the left side and MEG-only events on the right side. The software is assuming both sides are MEG and so the HEG events show up as even-numbered MEG orders. A preliminary spectral extraction of the MEG data, Figure below right, shows a nice spectrum but also a slight mis-registration of the response and the data at around 23 A --- a symptom of not having an accurate zeroth-order location. We expect to overcome these difficulties - stay tuned!

 


EXO 0748 and HerX-1

 

A key feature often seen in the spectra of binaries is the signature of photo-ionized emission coming from the matter (accretion disk) orbiting the compact object. In high inclination systems the bright continuum emission from the central source can be eclipsed by the companion star and/or attenuated as warps or bulges in the accretion disk come into the line of sight. By looking at the spectra in these dips and eclipses (and also Type I bursts from the compact object surface) the accretion disk structure can be probed. HETG Post Doc Mario Jimenez-Garate has developed and applied photo-ionization models to data from our GTO target EXO 0748-676 (ApJ 590:432-444, 2003) and to his own recent GO ToO observations of Her X-1.

In the case of Her X-1, in a paper submiited for publication, Jimenez-Garate presents measures of the He-like triplets in the data and uses the R-ratio (f/i) from Mg XI, lower left Figure, as one ingredient in constraining the density and location of the emitting material, lower right Figure.

 

 

 

Survey and Analysis of Piled-up HETGS Binary Observations

In general pileup in the HETG spectra is not a problem – but for bright X-ray Binary sources pileup may be the rule rather than the exception especially around 2 keV in the MEG spectra. John Davis and Norbert Schulz, both of the CXC at MIT, have started an analysis of all available HETG binary observations focusing in particular on including the effects of pile-up in the dispersed spectra.

 

“Some of these sources are so bright that there are many counts in a bin. Hence, the chi-square values are driven by systematic uncertainties in the data,” says John Davis. In the Fall of 2003 he developed a new model that would better account for differences between the front-side and back-side chips; it adds three additional fixed parameters per CCD. When those parameters were (laboriously) fit by simultaneously fitting several data sets the chi-square values dropped from, e.g., 7 per degree-of-freedom to less than 2 –-- a very significant improvement in the fit quality, e.g. see the Figure at right where systematics are generally below 5%.

 

The values of the new parameters depends on the calibration of the ACIS detector and the FI and BI QE values in particular; once these values are updated and released this project is ready to move on to the next stage.

 

 

 

 

SS 433 Results and Press Conference in Atlanta

 

The HETG group was quite pleased to have HETG data from GTO target SS 433 featured in a press release at the Atlanta AAS meeting:

 

 

http://chandra.harvard.edu/press/04_releases/press_010504.html

 

 

The press conference was given by MIT undergraduate Laura Lopez and her research supervisor Herman Marshall of CXC/MIT. The release included wonderful artist/scientist impressions of the SS 433 system created by CfA folks, diagrams of the system and jet geometries, and of course HETGS spectra showing the emission from the red and blue shifted jets and corresponding numerical model.

X-Ray Binaries Plans and Further Work

 

• Analyze Cycle 5 observation of 4U 1957+11 for warped disk signatures.

• Continue a catalogue of spectra from bright X-ray binaries corrected using pileup model.

• Continue to investigate the details of SS 433.

• Study the effect of resonance scattering in ionized stellar winds.

• Study models of photoionization in illuminated accretion disks.

• Study the X-ray spectra of black hole candidates with respect to their binary orbit, e.g. Cyg X-1.

• Look for absorption lines in X-ray burst spectra.

 

 

 

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

 

Analysis Software

Pileup correction software is used for the dispersed grating spectra for many XRB sources because they are so bright. Likewise, Continuous Clocking (CC) mode is often used for these observations and so CC software improvements have been driven by XRB observations. The brightest of all, Sco X-1, will allow/require light curve and timing software that works on dispersed data. The use of diffraction orders higher than the first is possible and necessary for these sources and so analysis s/w and calibration values for high-orders are put to use.

 

Modeling Software

In-house resonance scattering code is being developed for stellar wind systems. As mentioned above, we are carrying out photoionization modeling of accretion disk atmospheres.

 

 

4.4 Presentations, etc. (December and Jan. AAS Atlanta meeting)

 

Jimenez-Garate, “Using the X-ray Emission Lines of Seyfert 2's to Measure Abundance Ratios”, poster at Conference on Multiwavelength AGN Surveys, Cozumel Mexico, Dec. 2003.

 

K. Flanagan, “SNR 1E0102.2-7219 from a new angle”, poster at the 203rd AAS.

T. Jeltema, ”Cluster Substructure and its Evolution with Redshift” talk at the 203rd AAS.

M. Jimenez-Garate, “Accretion Disk Atmospheres around Kerr Black Holes”, talk at the 203rd AAS.

A. Juett, “[Oxygen edge measurements in the ISM]”, poster at the 203rd AAS.

L. Lopez, “Diagnostics of the Relativistic Jets of the Galactic X-ray Binary SS 433 Using the Chandra HETGS”, talk at the 203rd AAS.

P. Wojdowski, “Constraining the Wind Geometry in the High Mass X-ray Binary SMC X-1 with XMM/RGS Spectroscopy”, talk at the 203rd AAS.

 

 

 

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

 

K.A. Flanagan et al., “Chandra High-Resolution X-Ray Spectrum of Supernova Remnant 1E 0102.2-7219”, astro-ph/0312509, ApJ accepted, April 2004.

 

 

 

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 December.

 

6.0 Management

 

6.1 Program Office & NASA Support

 

No activities in this area in December.

 

6.2 MIT-internal management activities

 

In December Post Doc applications began arriving for the HETG Post Doc open starting September 2004.

 

 

7.0 Open Issues, Problems, etc.

 

There are no open issues or problems regarding the HETG.