# Presentation: 866544

## Update on science with Suzaku HXD

**G. Madejski, on behalf of the HXD Team: **
**K. Abe, Y. Ezoe, Y. Fukazawa, S. Hong, H. Inoue, K. Ito, T. Itoh, T. Kamae, D. Kasama, **
**M. Kawaharada, N. Kawano, K. Kawashima, S. Kawasoe, Y. Kobayashi, M. Kokubun, J. Kotoku, **
**M. Kouda, A. Kubota, K. Makishima, T. Mitani, H. Miyasaka, R. Miyawaki, K. Mori, M. Mori, **
**T. Murakami, M. Murashima, K. Nakazawa, H. Niko, M. Nomachi, M. Ohno, Y. Okada,**
** ****K. Oonuki, G. Sato, M. Suzuki, H. Takahashi, I. Takahashi, T. Takahashi, K. Tamura, T. Tanaka, **
**M. Tashiro, Y. Terada, S. Tominaga, S. Watanabe, K. Yamaoka, T. Yanagida, and D. Yonetoku**

- Collaborating institutions:  University of  Tokyo,  JAXA/ISAS, RIKEN,
-  Hiroshima Univ. , Saitama Univ. , Kanazawa Univ.,
- Aoyama Univ., Osaka Univ., SLAC, Clear Pulse Co. Ltd.

## HXD:  Detector design

- The Hard X-ray Detector is a non-imaging, collimated instrument sensitive from ~7 keV to ~600 keV
- It consists of the GSO/BGO scintillator counter (~30 - 600 keV), and the Si PIN diode (~7-70 keV)
- At E > ~ 100 keV (GSO), it is actively collimated to 4.5o x 4.5o
- At E < ~100 keV (PIN), it is passively collimated to 0.5o x 0.5o

## Science with the HXD

- Results from the HXD cover three areas:
- (1) Sensitive measurements of time-resolved broad band spectroscopy of bright sources (up to ~300 keV)
- (2) Measurements of hard X-ray continuum of faint sources
- (3) WAM results for gamma-ray bursts
- For a ~ 5 mCrab source, in 100 ks, the HXD can measure the continuum up to ~ 200 keV;  for a ~ 1 mCrab source, this will be only through the PIN range, up to ~ 50 keV

## Science with the HXD

- My focus here will be on part (2) - spectra, some admixture of part (1) – variability;                  examples are active galaxies
- By taxonomy of the different kind of AGN, I’ll consider the Seyfert galaxies and jet-dominated ones separately
- Seyferts:  the broad-band hard X-ray spectrum consists of primary continuum, with circum-nuclear spectral features, plus the Compton reflection component
- Circum-nuclear emission (mainly atomic spectral features – Fe K line, ...) is well studied with the XISs, while the HXD can determine the continuum precisely – especially at the highest energies
- The two new results are:
- (1) the primary continuum is a power law, but the cutoff, previously reported to be “universal” at ~ 200 keV, is *not* “universal” – some Seyferts show cutoffs at ~ 100 keV, others – no sign of cutoffs (MCG-5-23-16;  Reeves et al. 2007;  others)
- (2) the sensitivity of the HXD allows to study separately the variability of ingredients of the hard X-ray flux:  the Compton reflection component does not appear to vary in concert with the continuum (MCG-6-30-15;  Miniutti et al. 2007)

## Science with the HXD

- Another class of AGN studied with the HXD are jet-dominated objects, aka “blazars”

- * Example: 0836+714 (=4C71.07), one of most distant EGRET blazars, z = 2.172 shows a power law with  = 1.4 (SWG data;  paper in preparation)
- *  = 1.4 implies power law index of radiating particles
- p ~ 1.8 – tough  to produce in any particle acceleration scenario
- * The X-rays are likely produced by Compton upscattering of external, broad emission line photons or IR by highly relativistic electrons in the jet
- * Hard X-ray band uniquely probes the „bulk” of the radiating particles (can’t be studied via low  radio – contaminated by extended comp.)
- * Very important towards the determination of the jet content, and – because of the radiation environment of the host galaxy – the distance from the black hole where the jet forms

## Science with the HXD

- More blazar science:  possible detection of the “cold” particle component in the jet

- * PKS 1510-089 is another luminous blazar (z ~ 0.3), observed via the GO program by Suzaku, but also simultaneously by SWIFT (Kataoka, Madejski, Takahashi, et al. 2007)
- The broad-band spectrum shows a “soft excess” – signature of “cold” (non- or mildly-relativistic) electrons in the jet (aka “Sikora bump”)?
- Best results will be obtained by future observations joint with GLAST

- synchrotron

- Inverse Compton

- Blue bump

*“**Sikora bump?”*

## Science with the HXD

- Prospects for the GSO data for active galaxies

- * Good example:  SWG GTO observation of Cen A (Markowitz et al. 2007)
- The soft X-ray part is very rich in lines (Fe overabundance, ...) but above 10 keV, continuum dominates
- Even a ~100 ks observation provides GSO good detection to over 200 keV – here, power law with no break, no Compton reflection
- Is this due to the jet pointing somewhat away from the line of sight?

## Science with the HXD:  future – SNRs and Clusters

- Diffuse sources are also great targets:
- In supernova remnants, hard X-rays might point to the origin of cosmic rays
- Example: Cas-A (on the right), many others
- Hard X-ray emission from galaxy clusters is also expected – via energetic electrons (inferred from radio data) by Compton-scattering the CMB (see Abell 2029 on the right)
- Need careful understanding of PIN and GSO background, collecting dark Earth data, ...