Chandra News Issue 26, Summer 2019 20 Years of Chandra The X-Rays Also Rise Raffaella Margutti, Wen-fai Fong, Daryl Haggard Article on Page 1 Celebrating 20 Years of Chandra The year 2019 marks 20 years of superb performance by the Chandra X-ray Observatory. The CXC is planning a number of events and products for the science community and the general public. We give you an overview of plans on page 12. Complete up-to-date calendar of events http://cxc.cfa.harvard.edu/cdo/chandra20/ 20 Years of Chandra Science Symposium, Dec. 3–6 http://cxc.harvard.edu/symposium_2019/ Table of Contents The X-rays Also Rise: Chandra Observations of GW170817 Mark the Dawn of X-ray Studies of Gravitational Wave Sources � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 1 Director’s Log, Chandra Date: 670723206 � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 8 Project Scientist’s Report� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 9 Project Manager’s Report � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 11 Twenty Years of Chandra Celebrations � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 12 Remembering Riccardo Giacconi: The Father of X-ray Astronomy � � � � � � � � � � � � � � � � � 12 ACIS Update � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 17 HRC Update � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 19 HETG Update � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 20 LETG Update � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 25 Chandra Calibration Update � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 28 Chandra Source Catalog � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 29 CIAO 1.0 to CIAO 4.11: A World Apart � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 31 Chandra’s High Impact Science Papers � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 35 Rino Giordano (1955–2018) � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 37 Chandra Cool Targets (CCT, formerly CATs) � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 38 The NHFP Einstein Postdoctoral Fellowship Program � � � � � � � � � � � � � � � � � � � � � � � � � � � 39 Accretion in Stellar Systems � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 40 Twenty Years of Chandra Peer Reviews � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 46 Replacing RPS after 20 Years: Introducing New Chandra Proposal Software (CPS) � � � 51 The Chandra Newsletter appears once a year and is edited by Rodolfo Montez Jr., with editorial assistance and layout by Tara Gokas. We welcome contributions from readers. Comments on the newsletter, or corrections and additions to the hardcopy mailing list should be sent to: [email protected]. Follow the Chandra Director's Office on Facebook, Instagram, and Twitter (@ChandraCDO). Summer 2019 - 20 Years of Chandra 1 The X-rays Also Rise: Chandra 2017, Evans et al, 2017, Kasliwal et al. 2017, Kilpatrick et al. 2017, Lipunov et al. 2017, Nicholl et al. 2017, Pian et al. Observations of GW170817 Mark 2017, Shappee et al. 2017, Smartt et al. 2017, Soares-Santos the Dawn of X-ray Studies of et al. 2017, Tanvir et al. 2017, Valenti et al, 2017), known as “kilonova” (KN, proposed by Li & Paczyński,1998 see Gravitational Wave Sources Metzger 2017 for a recent review). The KN emission from GW170817 (and from BNS mergers) is powered by the Raffaella Margutti radioactive decay of heavy chemical elements produced Wen-fai Fong by the merger through “r-process’” nucleosynthesis, and Daryl Haggard tracks the slower moving material ejected by the collision, The Dawn of a New Era of Exploration with inferred velocities of ~0.1–0.3c (Cowperthwaite et al. 2017, Kasen et al. 2017, Smartt et al. 2017, Villar et al. The first extraterrestrial X-ray photons to be detected 2017, Tanvir et al. 2017). The observations of KN emission were those from the Sun in the late 1940s, followed in in GW170817 showed remarkable agreement with theoret- 1962 by the discovery of the first cosmic X-ray source: ical predictions on the luminosity evolution of the kilono- Scorpius X-1 (Giacconi, Gursky, Paolini & Rossi 1962). va emission at optical/NIR wavelengths (Metzger 2017b). Since then, for ~60 years the X-ray sky has revealed rich These observations signaled the birth of Multi-Messenger and violent phenomena, including jets from accreting Astrophysics (MMA) with GWs (Abbott et al. 2017a). black holes (BHs) and neutron stars (NSs), stellar explo- Models of compact-object mergers have also proposed sions, mergers, eruptions and disruptions (e.g., Seward & that these systems could launch energetic collimated out- Charles 2010). In August 2017, Chandra observations of flows reaching ultra-relativistic speeds (i.e., relativistic the gravitational wave (GW) event GW170817 marked the jets) and could be the progenitor systems of short gam- beginning of a new field: X-ray studies of sources of grav- ma-ray bursts (SGRBs, Eichler et al. 1989, Narayan et al. itational waves (Haggard et al. 2017, Margutti et al. 2017, Troja et al. 2017). 1992). The interaction of these relativistic outflows with The mergers of the most compact objects in nature (BHs the merger’s environment creates shocks that accelerate and NSs) emit GWs that are now detectable by the Laser particles which then cool by radiating photons. The radia- Interferometer Gravitational-wave and Virgo Observato- tion, produced by electrons gyrating in amplified magnet- ries (LIGO/Virgo). LIGO/Virgo has thus far detected ten ic fields (i.e., synchrotron), is non-thermal in nature and BH-BH mergers and one binary neutron star (BNS) merger dominates the observed emission at X-ray and radio wave- GW170817 (Abbott et al. 2017c, 2018). The BNS merger lengths at all times, where the contribution from the KN is GW170817 is the first GW event for which emission has negligible (Fig. 5). The resulting electromagnetic transient been observed across the entire electromagnetic spectrum, is thus an excellent probe of the physics of compact-object from the gamma-rays to the radio band, including soft mergers and their sub-parsec environments. The evolution X-rays. The X-ray emission from GW170817 was first of the resulting transient directly depends on the follow- captured by the sharp eyes of Chandra, which continues to ing factors: (i) amount of mass expelled by the catastrophic provide a detailed view of the rise and fall of the non-ther- collision, (ii) speed of expelled material, (iii) collimation mal (i.e., synchrotron) radiation associated with the fastest and direction with the line of sight, and (iv) density of the material flying out from the merger (Alexander 2018, Hag- circum-merger medium (e.g., Piran 2004). This is where gard et al. 2017, Margutti et al. 2017, 2018, Nynka et al. Chandra’s observations of GW170817 provided a funda- 2018, Piro et al. 2018, Pooley et al. 2018, Ruan et al. 2018, mental contribution to the nascent field of MMA with GWs. Troja 2017, 2018). Chandra X-ray observations of GW170817 provided GW170817 was detected by LIGO/Virgo on 17 August key constraints on the physical properties of the fastest 2017, and localized to within a 28 deg2 (90% confidence ejecta launched into space by the NS merger and on its region) area of the sky containing ~40 nearby galaxies environment (Alexander 2018, Haggard et al. 2017, Mar- at a distance of roughly 40 Mpc (Abbott et al. 2017b,c). gutti et al. 2017, 2018, Nynka et al. 2018, Piro et al. 2018, The GW detection was followed approximately two sec- Pooley et al. 2018, Ruan et al. 2018, Troja 2017, 2018). In onds later by the detection of gamma-rays from a consis- the following sections we highlight the impact of Chandra tent location in the sky (Abbott et al. 2017b, Goldstein et observations to constrain the nature of the X-ray emission al. 2017, Savchenko et al, 2017), and roughly half a day in GW170817. We also consider other potential sources of later by the detection of a rapidly-evolving transient shin- X-ray emission that did not play a major role in GW170817, ing brightly at UV/optical/NIR wavelengths (Arcavi et al. but might be relevant for future GW detections. Finally, 2017, Chornock et al. 2017, Coulter et al, 2017, Drout et al. we discuss other broad areas of astrophysics that can be 2 CXC Newsletter impacted by X-ray studies of GW sources and we end with the spectrum interestingly showed no evidence for any our views on discovery frontiers in the field. evolution (Fig. 5). At all times, the X-ray spectrum is well −0.6 Chandra Observations of GW170817 Reveal a described by a fairly hard power-law model with Fν~ ν Structured, Collimated, Relativistic Outflow in a and no evidence for intrinsic absorption, all of which is BNS Merger consistent with the low densities expected in the immedi- It all started with zero photons. The first deep X-ray ate environments of BNS mergers and the early-type nature observation of GW170817 was carried out by Chandra of the