Page History

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2021-05-13 - WG meeting on zoom

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2021 October 22nd  - Working group meeting     

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• Example for 2017 observations:

 

Image Modified	Model parameters from the 2017 observations Image Modified
Image Modified	Image Modified Cross normalization constants from the pairs of observations are shown on the left. Note: The Swift fluxes appear relatively high - perhaps due to the extraction annulus used - the analysis will be checked wit the Swift team Analysis above 1 keV chosen to avoid known soft excess in 3C 273 spectrum
Image Modified

• Communication with the Chandra team is underway to check the Chandra analysis
  • The NuSTAR analysis will be redone with the updated calibration released this month (2021 October)
• NICER observations will also be folded into the analysis (Renee Ludlam)
• Analysis will be extended to evaluate within the concordance framework (arXiv)
  • Flux ratio examined in narrow energy bands - model independent
• There is some complexity to the XMM spectrum - Felix Fuerst
  • with correlated residuals between instruments
• Work is continuing and will include the 2021 XMM-Newton observations as well as the NICER observations.

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• 1ES 0229+200 is a faint source for Astrosat-SXT, 74 ks exposure obtained in 2021 August
• Modeled as an absorbed power law
  • Excess above 5 keV may be due to background and features below 0.5 keV may be residual calibration artifacts
• Astrosat-UVIT data is yet to be released
• There is also a previous observation by Astrosat (that may not be available yet)

ActionsAction Items:

• Jamie Kennea - will contact Andy B. to see if Swift-XRT 2021 data for 1ES 0229+200 will be analyzed
• Renee Ludlam - Will work with Felix F. on joint analysis of NICER observations of 1ES 0229+200 

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The meeting concluded after a discussion about supporting IXPE in-flight calibration

• Launch scheduled for Dec 9th, 2021
  • A preliminary long term plan is available at https://ixpe.msfc.nasa.gov/for_scientists/ltp.html
• There are many coordinated observations approved for scientific programs with INTEGRAL, XMM-Newton, NuSTAR, etc.

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  • • Some may be useful for cross-calibration

   

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  2021 May 13th - Working group meeting     

   

  Held on Zoom

   

  Attending (in alphabetical order): 

  
  

  Dipankar Bhattacharya, Karl Forster, Felix Fuerst, Jamie Kennea, Kristin Madsen, Herman Marshall, Eric Miller, Katja Pottschmidt,  Celia Sanchez, Norbert Schartel, Michael Smith, Allyn Tennant, Yukikatsu Terada, Panayiotis Tzanavaris, Josh Wing

  Review status of working group

  • The chair has been very quiet since the last IACHEC meeting in May 2019 (apologies). 
  • Membership is open to all and has 60 colleagues subscribed to the WG slack channel (#coordinated-obs)
  • Cross-calibration observations on 3C 273 were coordinated (thanks to Josh W. for starting the ball rolling with Chandra constraints each year)
    • 2019-07-02 to 03 - Chandra, INTEGRAL, NICER, NuSTAR, Swift, XMM
    • 2020-07-06 to 07 - Chandra, INTEGRAL, NICER, NuSTAR, Swift, XMM
  • Communications
    • There were no strong opinions about how best to communicate between WG members. Currently:
      • email chair (Karl F.)      krl _at_ srl.caltech.edu
      • Slack channel:    iachec.slack.com
      • an email list server (hosted by Caltech) may be set up by Karl F. depending on what the other WG’s think (particularly the communications WG).
        • DONE - iachec-co-obs@lists.srl.caltech.edu is active
  • Dissemination of observation scheduling information
    • International standards for target visibility and observation schedules have been developed by a team at ESAC, see  https://www.cosmos.esa.int/web/vovisobs_protocols/home
    • A client using these standards (ObjVisSAP, ObsLocTAP) implemented for INTEGRAL, XMM-Newton, Chandra, and NuSTAR is active (TOBY), see   http://integral.esa.int/toby/
      • (just click on the Calculate button to get latest schedules)
    • Observatories are joining the callobaration (GAIA, NOT, MAGIC, XRISM)
      • All IACHEC observatories are encouraged to join
    • See also SmartNet    http://www.isdc.unige.ch/smartnet/index.php
    • Information about calibration targets and upcoming observations collected in google sheets  
      • https://docs.google.com/spreadsheets/d/1EA_7c0J2c4kX62t-qoVDLXJiE0SkS8sqZiBjokJbUKs/edit?usp=sharing
      • including a timeline
        
        

  
  

  A/I   Request that WG chairs look at lists on the google sheets and make/suggest additions/corrections

  2021 3C 273 Cross-calibration campaign

  • Confirmed observations scheduled for 2021 June 9th to 11th with Chandra, INTEGRAL, NuSTAR, XMM

  A/I   Swift - Jamie K. thinks it likely that Swift will perform some observations - will contact Andy B. to check

  A/I   NICER - Karl F. will contact NICER team to see if they will join

   

  • Kristin M. is advising two SURF students this (2021) summer in analysis of 3C 273 data taken since 2015

   

  Mission	2015	(ks)	2016	(ks)	2017	(ks)	2018	(ks)	2019	(ks)	2020	(ks)	2021
  Chandra	2015-07-14	30	2016-06-27	30	2017-06-26	27	2018-07-04	30	2019-07-03	30	2020-07-06	29	Y
  INTEGRAL	2015-07-13	150	2016-06-26	100	2017-06-26	175	2018-07-04	100	2019-07-02	100	2020-07-04	120	Y
  NICER							2018-07-09	1.5	2019-06-30	38	2020-07-08	25	?
  NuSTAR	2015-07-13	49	2016-06-26	35	2017-06-26	35	2018-07-04	40	2019-07-02	49	2020-07-06	44	Y
  Swift	2015-07-12	18	2016-06-26	40	2017-06-23	22	2018-07-14	17	2019-07-12	16	2020-07-16	18	?
  XMM	2015-07-13	72	2016-06-26	67	2017-06-26	67	2018-07-04	78	2019-07-02	69	2020-07-06	70	Y

   

  • This will be an update to Madsen et al. (2017) AJ 153, 2     https://iopscience.iop.org/article/10.3847/1538-3881/153/1/2

  A/I   Kristin M. Requests the teams (Chandra, Swift, XMM, NICER) provide (processed) data ready for joint analysis

   

  • It has always been difficult for Astrosat to join because 3C 273 is at low declination
  • 3C 273 is a good target for XMM-RGS but there is pileup for EPIC instruments

  A/I   Karl F. will contact Konrad D. to see if SRG-eROSITA/ART-XC has survey footprint close to dates of IACHEC campaigns 

  Additional cross-calibration opportunities

  • NuSTAR / XMM-Newton observations of the Crab in 2020/22
    • Leading to revised calibration expected in 2021
  • Insight-HXMT will join in future observations - Lian T.

  IACHEC Support for in-flight calibration of upcoming missions

   

  IXPE - From Allyn T.

  • Launch planned for 2021 November 17th
    • Science observations begin around mid-December
  • Target Visibility will be 90 deg from the Sun +/- 25 deg
  • For observatory verification plan to observe:
    • Crab: Two half-day observations separated by about a week (due to telemetry limit)
    • 1ES 1959+650: used to check alignments - good target for IXPE as it is close to NEP and not too bright or faint

  A/I   Begin scheduling discussions a few months before launch (discuss details at September IACHEC meeting?)

  • From Herman M. 
    • May also use Cyg X-1 in observatory verification
    • Must be careful not to perform observations that potentially step on goals of science investigations
  • Other coordinations?
    • Astrosat-CZTI - Dipankar B.
      • Polarization seen in Crab data and possibly Cyg X-1
    • However - energy range (>100 keV) not close to IXPE (< 10 keV) so cross-calibration is likely to be a science investigation
  • Other polarization missions?
    • POLSTAR - not launched
    • polarlight - GPD 

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