Accepted Cycle 16 Observing Proposals

BH AND NS BINARIES

Proposal Number	Subject Category	PI Name	Type	Time (ks)	Title
16400006	BH AND NS BINARIES	Kaastra	GTO/TOO	80	Hunting for discrete spectral features in the Rapid Burster
16400093	BH AND NS BINARIES	Prestwich	GO	75	Is there an HLX in the Lyman-alpha Galaxy Haro 11?
16400124	BH AND NS BINARIES	Ajello	TOO	10	CHANDRA TOOs FOR FERMI GALACTIC PLANE TRANSIENTS
16400143	BH AND NS BINARIES	Paizis	TOO	20	INVESTIGATING NEW INTEGRAL SOURCES WITH Chandra
16400153	BH AND NS BINARIES	Pooley	TOO	20	Transient LMXBs in Globular Clusters
16400196	BH AND NS BINARIES	Plotkin	TOO	135	Following a black hole X-ray transient through the transition into quiescence
16400255	BH AND NS BINARIES	Israel	GO	40	Glimpsing a Chandra Population of new X-ray Pulsators
16400288	BH AND NS BINARIES	Miller	TOO	80	Wind-Triggered Disk Wind Spectroscopy of GRS 1915+105
16400294	BH AND NS BINARIES	Miller	TOO	120	The Ins and Outs of Disk Accetion in Black Hole Transient
16400301	BH AND NS BINARIES	Strader	GO	33	A Black Hole in the Galactic Globular Cluster M10
16400324	BH AND NS BINARIES	Corbel	TOO	150	X-Ray Jets in Microquasars
16400332	BH AND NS BINARIES	Diaz Trigo	TOO	100	A STUDY OF THE RELATIVISTIC JET OF 4U1630-47
16400369	BH AND NS BINARIES	Jonker	TOO	200	Chandra ToO observations of Gaia-discovered tidal disruption events
16400393	BH AND NS BINARIES	Chakrabarty	TOO	150	Narrow Lines from a Slowly Rotating Neutron Star
16400423	BH AND NS BINARIES	Wijnands	TOO	150	Crust cooling of accretion-heated neutron stars
16400444	BH AND NS BINARIES	Chakrabarty	TOO	4	Precise Localization of Transient Low-Mass X-ray Binaries
16400466	BH AND NS BINARIES	King	TOO	80	Following the Ultra-Fast Winds in the Stellar-Mass Black Hole, IGR 17091-3624
16400507	BH AND NS BINARIES	Cackett	GO	150	Crustal cooling from KS 1731-260 14 years into quiescence
16400537	BH AND NS BINARIES	Grinberg	TOO	24	Filling the gap in understanding the wind structure of HDE 226868 /Cyg X-1
16400546	BH AND NS BINARIES	Degenaar	GO	45	The nature of the transient X-ray binary Swift J1910.2-0546
16400552	BH AND NS BINARIES	Laffon	GO	20	Looking for evidence of a pulsar wind nebula or a gamma-ray binary associated with the TeV source HESS J1832-093
16400577	BH AND NS BINARIES	Neilsen	TOO	120	An Integrated Approach to Winds, Jets, and State Transitions
16400639	BH AND NS BINARIES	Homan	TOO	32	The short-orbital-period black-hole X-ray binary Swift J1753.5-0127 in quiescence
16400764	BH AND NS BINARIES	Brorby	GO	70	X-RAYS FROM GREEN PEA ANALOGS
16400845	BH AND NS BINARIES	Li	GO	46	Ultraluminous X-rays from the historical supernova 1986L: Testing stellar mass black hole scenario for the ULX origin
16400852	BH AND NS BINARIES	Strohmayer	GO	100	Constraining Neutron Star Properties with Chandra Observations of Millisecond Pulsars
16400865	BH AND NS BINARIES	Linares	GO	90	Spying on millisecond pulsar paradise: Chandra+GBT monitoring of M28
16400867	BH AND NS BINARIES	Nowak	GO	20	What is the Orbital Period of the Hierarchical Triple Candidate 4U 2129+47?
16400877	BH AND NS BINARIES	Walton	TOO	100	Broadband X-ray Observations of a High-State from the Hyper-luminous X-ray Source M82 X-1
16400905	BH AND NS BINARIES	Ribo	GO	60	Accretion/ejection coupling in the first Be/BH system

Subject Category: BH AND NS BINARIES

Proposal Number: 16400006

Title: Hunting for discrete spectral features in the Rapid Burster

Type: GTO/TOO Total Time (ks): 80

PI Name: Jelle Kaastra

Abstract: We propose to carry out a 80ks HETGS observation of the low-mass X-ray binary MXB 1730-335. Our goal is to detect spectral features originating in the photosphere during type I bursts, which would allow to determine the gravitational redshift. The exceptionally short burst recurrence times shown by the source and the minor Doppler broadening of spectral features due to its likely slow rotation facilitate the detection. Furthermore, RXTE-PCA observations have shown ~30s dips due to an increased column density of the absorbing material during some type I bursts. If repeated with Chandra, such observations may diagnose the absorber in the circumstellar environment.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+17:33:24.60	-33:23:19.90	MXB 1730-335	ACIS-S	HETG	80.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400093

Title: Is there an HLX in the Lyman-alpha Galaxy Haro 11?

Type: GO Total Time (ks): 75

PI Name: Andrea Prestwich

Abstract: Haro-11 is a famous compact dwarf galaxy undergoing an intense starburst. It is also an example of a Lyman-alpha emitting galaxy. We show that there is an extremely luminous (Lx~1E41 ergs/s) compact X-ray source located at the center of a bipolar Lyman alpha nebula. This source may be a Hyperluminous X-ray source. We ask for 3 monitoring observations of this source on a timescale of years to detect high amplitude variability which would indicate the presence of a HLX. The fact that the candidate HLX is associated with a Lyyman alpha nebula raises the exciting possibility that winds from the HLX (possibly an IMBH) play an important role in blowing away the neutral gas to allow the Lyman alpha to escape.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+00:36:52.70	-33:33:16.90	Haro 11	ACIS-S	None	75.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400124

Title: CHANDRA TOOs FOR FERMI GALACTIC PLANE TRANSIENTS

Type: TOO Total Time (ks): 10

PI Name: Marco Ajello

Abstract: Fermi detected hundreds of transients with short (sec to hr) and long (months) variability timescales. However, so far no systematic search of transients on weekly timescales has been performed. The Fermi All-sky Variability Analysis (FAVA) allows us to systematically search all-sky for weekly transients. The novelty of FAVA resides in using the mission-long data to provide an estimate of the average sky intensity against which weekly data are compared. This makes FAVA an unbiased and fast tool to find transients in the Galactic plane where the diffuse emission is the brightest. FAVA detects 1 plane transient every 8 weeks. We propose to use Chandra to follow up on 2 new transients. The population of Galactic transients is under-sampled and detecting even 1 source will have a large impact

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
		FAVA Transient 1	ACIS-I	None	10.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400143

Title: INVESTIGATING NEW INTEGRAL SOURCES WITH Chandra

Type: TOO Total Time (ks): 20

PI Name: Adamantia Paizis

Abstract: We propose to trigger a maximum of 2 Chandra fast (4-15 days) ToO observations on new sources discovered by INTEGRAL. We ask for 20 ksec per observation, using HETGS. The scientific aims are: 1) determine the source position with Chandra unique sub-arcsecond accuracy, which will allow our team to perform source identification and multi-wavelength follow-up observations, crucial in the crowded Galactic plane and center regions; 2) obtain the high resolution HETGS X-ray spectrum, free from pile-up distortions, crucial to determine the nature of the new source. We aim to continue our successful INTEGRAL-Chandra monitoring program begun in Chandra AO 5.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
		New INTEGRAL source 1	ACIS-S	HETG	20.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400153

Title: Transient LMXBs in Globular Clusters

Type: TOO Total Time (ks): 20

PI Name: David Pooley

Abstract: Since the discovery of globular cluster LMXBs in the 1970s, it was assumed that there was only one luminous LMXB per cluster. Deep Chandra observations of several globular clusters have revealed that they contain numerous quiescent LMXB systems, any of which could go into outburst. Our observations will determine the precise locations of new outbursts from transient LMXBs in globular clusters, enabling the important study of their quiescent counterparts.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
		GC Transient 1	HRC-S	None	10.0
		GC Transient 2	HRC-S	None	10.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400196

Title: Following a black hole X-ray transient through the transition into quiescence

Type: TOO Total Time (ks): 135

PI Name: Richard Plotkin

Abstract: There is increasing evidence that the quiescent state of black hole X-ray binaries (BHXBs) is different from the canonical hard state at higher luminosities. Quiescent BHXB X-ray spectra are generally softer, and it has recently been realized that not every system takes the same path through the radio/X-ray luminosity plane during the decay into quiescence. We request six simultaneous Chandra/VLA TOO observations to monitor a BHXB during an outburst decay between 3e-7--1e-4 L_Edd, a crucial luminosity regime that represents the transition into quiescence for many systems, but still has sparse data coverage. From these coordinated observations we will place new constraints on jet-dominated and radiatively inefficient accretion flow models.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
		Fading BHXB (TOO)	ACIS-S	HETG	135.0
		Fading BHXB (TOO)	ACIS-S	None	None

Subject Category: BH AND NS BINARIES

Proposal Number: 16400255

Title: Glimpsing a Chandra Population of new X-ray Pulsators

Type: GO Total Time (ks): 40

PI Name: Gianluca Israel

Abstract: In the largest ever systematic search in soft X-rays for coherent periodicities [more than 400,000 light curves collected by the Swift X-Ray Telescope and the Chandra Advanced CCD Imaging Spectrometer] we have discovered so far about 35 new X-ray pulsators. In this proposal we ask for Chandra follow-ups for two of them, for which the discovery Chandra observations are covering only a few cycles of the detected signals and no further high energy archival data are available. The requested observations will allow us to: i) unveil their nature, ii) extending our understanding of the physics of accretion toward lower luminosities and iii) test magnetic gating accretion scenarios, a regime which has remained poorly explored so far.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+17:10:04.70	-32:12:07.00	CXOUJ171004.7	ACIS-S	None	40.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400288

Title: Wind-Triggered Disk Wind Spectroscopy of GRS 1915+105

Type: TOO Total Time (ks): 80

PI Name: Jon Miller

Abstract: In soft spectral states, GRS 1915+105 launches a remarkable disk wind. This flow may carry away a substantial fraction of the accreting material, so it is critical to understand how it is launched and regulated. Using dedicated Swift/XRT observations that can detect strong Fe XXV and Fe XXVI absorption lines, we propose to trigger 3 new 40 ks Chandra/HETG observations of a strong wind phase in GRS 1915+105. We will study the duration and evolution of the outflow rate and kinetic power, and search for multiple components in the wind that may help to probe launching mechanisms.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+19:15:11.60	+10:56:44.80	GRS 1915+105	ACIS-S	HETG	80.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400294

Title: The Ins and Outs of Disk Accetion in Black Hole Transient

Type: TOO Total Time (ks): 120

PI Name: Jon Miller

Abstract: Stellar-mass black holes are excellent laboratories in which to study the fundamental physics of disk accretion, radiative and mechanical feedback from black holes, and in which to explore the predictions of general relativity. In order to make progress on these fronts, and to better explore emerging connections between the disk, winds, and jets, we propose to observe a bright black hole transient (new, or previously known) in outburst on 3 occasions using the HETGS, for 40 ksec each time. Independent Swift and optical programs will support this proposal.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
		Black Hole Transient	ACIS-S	HETG	120.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400301

Title: A Black Hole in the Galactic Globular Cluster M10

Type: GO Total Time (ks): 33

PI Name: Jay Strader

Abstract: As part of our deep radio continuum survey of Milky Way globular clusters, we have discovered a new radio-selected candidate stellar-mass black hole binary in the cluster M10. We request 33 ksec of Chandra imaging to determine whether this source has an X-ray counterpart consistent with that expected for a quiescent stellar-mass black hole.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+16:57:09.00	-04:06:01.10	M10	ACIS-S	None	33.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400324

Title: X-Ray Jets in Microquasars

Type: TOO Total Time (ks): 150

PI Name: Stephane Corbel

Abstract: We propose Target of Opportunity (ToO) observations for detailed studies of X-ray jets from microquasars. We describe our discovery of radio/X-ray jets in three microquasars, why X-ray jets are probably much more common than previously thought, and transient X-ray jets offer an exciting new way to probe the physics of relativistic jets from black holes. The proposed ToO observations are optimized to discover and study (flux evolution, morphology, SED, proper motion, ...) of new X-ray jets from microquasars, triggered by their detection as radio lobes. This will have implications not only for the study of jets from Galactic X-ray binaries, but also for our understanding of relativistic jets from active galactic nuclei (AGN).

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
		X-ray Jets	ACIS-S	None	150.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400332

Title: A STUDY OF THE RELATIVISTIC JET OF 4U1630-47

Type: TOO Total Time (ks): 100

PI Name: Maria Diaz Trigo

Abstract: We propose one 100ks observation of the high inclination black hole (BH) low mass X-ray binary (LMXB) 4U1630-47 in a very high state of accretion. We will attempt to confirm the presence of the narrow emission features observed in a recent XMM spectrum of the source that we interpreted as Doppler-shifted lines from a relativistic, bipolar jet. Chandra/HETGS spectra have proven invaluable to study the jet in the supercritical accreting source SS 433. The detection of such features in a canonical BH LMXB transient opens a new window for the understanding of jets and launching mechanisms via the detection of baryons, and precise measurements of speed and opening angle of the jet. The simultaneous radio observation will prove if the X-ray lines, should they be detected, originate in a jet.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+16:34:01.60	-47:23:34.00	4U 1630-47	ACIS-S	HETG	100.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400369

Title: Chandra ToO observations of Gaia-discovered tidal disruption events

Type: TOO Total Time (ks): 200

PI Name: Peter Jonker

Abstract: The Gaia satellite is predicted to discover more than 100 Tidal Disruption Events per year. A small fraction should have X-ray emission bright enough to allow detailed Chandra follow-up observations. These observations can be compared with the theoretical predictions for the outflows and presence of absorption lines and edges. Tidal disruption events are also our only way to determine black hole properties of otherwise dormant black holes in galaxies beyond a few local galaxies.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+00:00:00.00	+00:00:00.00	Gaia-TDE-imbh	ACIS-S	None	200.0
+00:00:00.00	+00:00:00.00	Gaia-TDE-imbh	ACIS-S	None	None

Subject Category: BH AND NS BINARIES

Proposal Number: 16400393

Title: Narrow Lines from a Slowly Rotating Neutron Star

Type: TOO Total Time (ks): 150

PI Name: Deepto Chakrabarty

Abstract: The detection and identification of photospheric absorption lines from a neutron star would allow measurement of its gravitational redshift and hence the neutron star compactness. In principle, the line shape allows unique determination of mass and radius separately. X-ray bursters are, in most respects, the ideal targets for this search, but most rotate so rapidly that any lines are too broadened to detect. However, the recently discovered X-ray burster Terzan 5 X-2 spins at only 11 Hz, 20 times slower than the next slowest rotator. We propose a TOO observation with HETGS to search for narrow lines of ionized Fe when this X-ray transient next becomes active. This is the best chance ever to detect a narrow atomic line in a neutron star.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+17:48:04.80	-24:46:48.80	IGR J17480-2446	ACIS-S	HETG	150.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400423

Title: Crust cooling of accretion-heated neutron stars

Type: TOO Total Time (ks): 150

PI Name: Rudy Wijnands

Abstract: We propose to continue our successful program to use the observed cooling of the crusts in accreting neutron star systems to probe the properties of ultra-dense matter. Those crusts are heated due to the accretion of matter onto neutron stars during the X-ray outburst and after the outbursts are over the crusts should cool down until they are in equilibrium with the core again. Following this cooling processes in several systems has already given us new insights in the structure of neutron stars (i.e., the crust but also the core and hence in ultra dense matter), but many uncertainties remain. Therefore it is needed to enlarge our sample of well studied sources to obtain better insights in the behavior of how neutron stars react to the accretion of matter.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
		Quiescent source	ACIS-S	None	150.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400444

Title: Precise Localization of Transient Low-Mass X-ray Binaries

Type: TOO Total Time (ks): 4

PI Name: Deepto Chakrabarty

Abstract: We propose to observe up to four neutron star or black hole transients in outburst to obtain accurate source positions, continuing a successful multi-year and multiwavelength program in place since Cycle 6. These positions and their prompt dissemination will allow re-observation of these sources in the X-ray, optical, IR, and radio bands in order to study their quiescent emission and to enable detailed follow-up (e.g., orbital radial velocity spectroscopy). This program will increase the number of accurately-positioned X-ray transients, providing a more uniform sample for future studies. We will only trigger our program for sources in crowded or highly obscured fields where a position from another mission (e.g., Swift) is insufficiently precise.

Target Name	Det.	Grating	Exp. Time (ks)
X-ray transient 1	ACIS-S	None	1.0
X-ray transient 2	ACIS-S	None	1.0
X-ray transient 3	ACIS-S	None	1.0
X-ray transient 4	ACIS-S	None	1.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400466

Title: Following the Ultra-Fast Winds in the Stellar-Mass Black Hole, IGR 17091-3624

Type: TOO Total Time (ks): 80

PI Name: Ashley King

Abstract: IGR J17091-3624 is the first stellar-mass black hole candidate to show evidence for ultra-fast winds, v/c=0.03. We propose a triggered campaign that will follow IGR J17091-3625 throughout a new outburst, tracking the evolution of its ultra-fast wind. Understanding the strength, ionization, velocity structure, variability and ultimately, the duty cycle of this ultra-fast wind is the key to understanding the disk-wind-jet connection in this source, and potentially in super-massive black holes. We propose a triggered campaign of IGR J17091$-$3624 with 4$\times$ 40 ksec observations spaced 30 days apart.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+17:09:07.60	-36:24:24.90	IGR J17091-3624	ACIS-S	HETG	80.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400507

Title: Crustal cooling from KS 1731-260 14 years into quiescence

Type: GO Total Time (ks): 150

PI Name: Edward Cackett

Abstract: The cooling of accretion-heated neutron star crusts after a return to quiescence provides a rare opportunity to investigate neutron star structure. The first source where crustal cooling was observed is KS 1731-260, which has been in quiescence since 2001. Our successful long-term Chandra monitoring of this source has shown that the crust must have a high thermal conductivity - the first constraint of this kind. However, several other crustal cooling sources have recently shown unexpected behavior in their cooling curves at late times. Here we are proposing a 150 ks observation of KS 1731-260 to determine the state of the crust 14 years into quiescence, allowing us to constrain the crust thickness (and hence surface gravity) and core temperature.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+17:34:13.50	-26:05:18.60	KS 1731-260	ACIS-S	None	150.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400537

Title: Filling the gap in understanding the wind structure of HDE 226868 /Cyg X-1

Type: TOO Total Time (ks): 24

PI Name: Victoria Grinberg

Abstract: We propose to observe the BH HMXB system HDE 226868 /Cyg X-1 as a ToO with Chandra-HETGS for 24 ks (corresponding to Delta phi=0.05 in orbital phase) between orbital phases phi=0.25 and phi =0.4. The spectroscopic analysis of the highly photoionized wind during this phase will improve our understanding of the wind, its implications for the accretion flow onto the black hole, and also of the conditions necessary for the formation of a narrow Fe K fluorescence line. In addition, during this phase dipping, which is very prominent at phi~=0, is expected to cease. The morphology and spectral signatures of the very last observed dips will constrain the location and kinematics of the wind structures responsible for these absorption events.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+19:58:21.70	+35:12:05.80	Cyg X-1	ACIS-S	HETG	24.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400546

Title: The nature of the transient X-ray binary Swift J1910.2-0546

Type: GO Total Time (ks): 45

PI Name: Nathalie Degenaar

Abstract: Swift J1910.2-0546 is a newly discovered transient X-ray binary that exhibited a ~1 yr long outburst in 2012-2013. Owing to its low hydrogen column density and fair proximity, it is one of the few sources for which X-ray/UV quiescent studies are feasible. This provides the opportunity to verify the nature of the compact primary (black hole versus neutron star), and to investigate the properties of the quiescent accretion flow. Such a study would provide an important perspective to understand the intriguing outburst phenomena observed for this source. To this end, we request a 45 ks Chandra/ACIS-S observation and 2 orbits of HST/WFC3-UVIS time for Swift J1910.2-0546.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+19:10:22.80	-05:47:46.30	Swift J1910.2-0546	ACIS-S	None	45.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400552

Title: Looking for evidence of a pulsar wind nebula or a gamma-ray binary associated with the TeV source HESS J1832-093

Type: GO Total Time (ks): 20

PI Name: Helene Laffon

Abstract: The newly discovered TeV source HESS J1832-093 observed on the rim of SNR G22.7-0.2 remains unidentified despite extensive multi-wavelength study. XMM-Newton observations allowed the discovery of a hard point-like source as a potential counterpart but its nature could not be confirmed. A compelling IR counterpart to the X-ray source is found in the 2MASS catalog. The origin of the TeV emission could stem from a pulsar wind nebula or a new gamma-ray binary. The very good Chandra angular resolution could probe for smaller source extensions and therefore detect an extended X-ray nebula which would confirm the PWN scenario. On the other hand, Chandra could measure the X-ray source localization very accurately and determine the association with the 2MASS source, favoring the binary possibility.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+18:32:45.00	-09:21:53.90	XMMU J183245-0921539	ACIS-I	None	20.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400577

Title: An Integrated Approach to Winds, Jets, and State Transitions

Type: TOO Total Time (ks): 120

PI Name: Joseph Neilsen

Abstract: We propose a large multiwavelength campaign (120 ks Chandra HETGS, NuSTAR, INTEGRAL, JVLA/ATCA, Swift) on a black hole transient to study the influence of ionized winds on relativistic jets and state transitions. With a reimagined observing strategy based on new results on integrated RMS variability and a decade of radio/X-ray monitoring, we will search for winds before the state transition to test their influence on and track their coevolution with the disk and the jet over the next ~2 months.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
		Black Hole Transient	ACIS-S	HETG	120.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400639

Title: The short-orbital-period black-hole X-ray binary Swift J1753.5-0127 in quiescence

Type: TOO Total Time (ks): 32

PI Name: Jeroen Homan

Abstract: We propose a Chandra observation of Swift J1753.5-0127 (J1753), one of the shortest-orbital-period black-hole LMXBs. Observing this source in quiescence allows us to test whether there exists a minimum luminosity for quiescent BH LMXBs, as predicted by binary-evolution theory and hinted at by recent observations of two other short-orbital-period BH LMXBs. This observation is also relevant for the comparison between quiescent neutron star and BH LMXBs, since the orbital period of J1753 falls in a range that is still sparsely populated by BHs; such a comparison can provide further insight into the differences between the radiatively inefficient flows in both types of systems. For a distance of 4 kpc we will be able to detect J1753 down to a luminosity of ~3e30 erg/s in 32 ks with ACIS-S.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+17:53:28.30	-01:27:06.20	Swift J1753.5-0127	ACIS-S	None	32.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400764

Title: X-RAYS FROM GREEN PEA ANALOGS

Type: GO Total Time (ks): 70

PI Name: Matthew Brorby

Abstract: X-rays may have contributed to the heating and reionization of the IGM in the early universe. High mass X-ray binaries (HMXB) within small, low-metallicity galaxies are expected to be the main source of X-rays at this time. Since studying these high-redshift galaxies is currently impossible, we turn to local analogs that have the same properties the galaxies in the early are expected to have. A number of recent studies have shown an enhanced number of HMXBs in nearby low metallicity galaxies. We propose to observe a sample of metal-deficient luminous compact galaxies (LCG) in order to determine if the X-ray luminosity is enhanced relative to SFR, thereby providing further evidence to the importance of X-rays in the early universe.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+14:48:05.30	-01:10:57.70	SHOC 486	ACIS-S	None	24.0
+08:42:20.90	+11:50:00.20	SDSS J084220.94+115000.3	ACIS-S	None	46.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400845

Title: Ultraluminous X-rays from the historical supernova 1986L: Testing stellar mass black hole scenario for the ULX origin

Type: GO Total Time (ks): 46

PI Name: Kwan Lok Li

Abstract: The Type II-L SN 1986L was first discovered in X-ray through serendipitous Swift observations taken in 2005 and 2007 with a luminosity of 1.6*10^40 erg/s which is reminiscent of ULX that could either be an IMBH or a stellar mass black hole at (super-)Eddington accretion. While Type II-L SNe are suggested to explode in binary, we suspect that a stellar mass black hole remnant created by fallback forming an X-ray binary with the progenitor's companion to produce the ULX. As the positional accuracy of Swift prevents a solid identification, a deep Chandra observation is required to confirm the SN-ULX association. If confirmed, SN 1986L will be the first ULX detected in a young SNR, which favors the stellar mass black hole scenario.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+04:17:29.40	-62:47:04.00	SN 1986L	ACIS-S	None	46.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400852

Title: Constraining Neutron Star Properties with Chandra Observations of Millisecond Pulsars

Type: GO Total Time (ks): 100

PI Name: Tod Strohmayer

Abstract: Neutron star observables influenced by r-mode physics, such as their spin and thermal evolution, can provide a unique window on their exotic interiors. We propose ACIS-S observations of four non-accreting millisecond pulsars (PSRs J1640+2224, J2019_2425, J1709+2313 and J1923+2515) with low inferred magnetic fields in order to constrain their neutron star surface temperatures, obtain limits on the amplitude of unstable r-modes in them, and make comparisons with similar limits obtained for a sample of accreting LMXB neutron stars. Perhaps surprisingly, none of our proposed targets is yet detected in the X-ray band. Our observations will provide the first X-ray detections of these objects, and will enable further exploration of the r-mode instability in neutron stars.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+16:40:16.70	+22:24:08.90	PSR J1640+2224	ACIS-S	None	40.0
+17:09:05.80	+23:13:27.80	PSR J1709+2313	ACIS-S	None	60.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400865

Title: Spying on millisecond pulsar paradise: Chandra+GBT monitoring of M28

Type: GO Total Time (ks): 90

PI Name: Manuel Linares

Abstract: We propose a coordinated Chandra and GBT program to monitor the millisecond pulsar population in the globular cluster M28, with a special focus on the unique transitional pulsar discovered last year. This unprecedented multi-wavelength campaign on a carefully selected cluster will bring us closer to understand how recycled pulsars are formed and how they interact with their surroundings.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+18:24:32.90	-24:52:11.40	M28	ACIS-S	None	90.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400867

Title: What is the Orbital Period of the Hierarchical Triple Candidate 4U 2129+47?

Type: GO Total Time (ks): 20

PI Name: MIke Nowak

Abstract: We propose to observe the neutron star system 4U 2129+47 whose X-ray and optical lightcurves show a modulation of around 5.2 hr. This is associated to orbital motion around an optical companion which, additionally, eclipses the X-ray source once every orbital period. We have found growing evidence that the system is indeed a hierarchical triple as we are able to fit the eclipse times with a model including the Doppler shift caused by the hypothetic third body. With the available data we can decrease the number of possible orbit solutions to two. Thus, we ask to observe 4U 2129+47 with Chandra again once during a specific date range for 22 ksec, specifically where the two possible orbital solutions differ most. This data will tell us immediately which orbital solution is correct.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+21:31:26.20	+47:17:24.00	4U 2129+47	ACIS-S	None	20.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400877

Title: Broadband X-ray Observations of a High-State from the Hyper-luminous X-ray Source M82 X-1

Type: TOO Total Time (ks): 100

PI Name: Dominic Walton

Abstract: Broadband X-ray spectroscopy of ultraluminous X-ray sources (ULXs) has begun to provide important information regarding the nature of these enigmatic sources. By far the most intriguing results come from cases where we have multi-epoch observations of sources that exhibit strong flux and spectral variability. We propose to undertake a 100 ks Chandra + NuSTAR ToO of the hyperluminous X-ray source M82 X-1 (L[X, peak] ~ 1e41 erg/s) in a high-flux state, in order to complement our existing broadband observations of M82 X-1 in a low state and investigate any spectral variability associated with this transition. Our planned use of the Chandra gratings will also allow us to place stringent constraints for the first time on the presence of any massive outflows launched by M82 X-1 in this state.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+09:55:50.20	+69:40:47.00	M82 X-1	ACIS-S	HETG	100.0

Subject Category: BH AND NS BINARIES

Proposal Number: 16400905

Title: Accretion/ejection coupling in the first Be/BH system

Type: GO Total Time (ks): 60

PI Name: Marc Ribo

Abstract: We propose to conduct deep joint Chandra and VLA observations of the recently discovered first Be/BH system to reach the following goals: 1) Obtain an accurate position of the source; 2) Determine its X-ray spectrum; 3) Search for X-ray flux variability; 4) Unveil the accretion/ejection coupling in HMXBs in quiescence.

R.A.	Dec.	Target Name	Det.	Grating	Exp. Time (ks)
+22:42:57.30	+44:43:18.30	MWC 656	ACIS-S	None	60.0

The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA. Email: cxchelp@head.cfa.harvard.edu Smithsonian Institution, Copyright © 1998-2024. All rights reserved.