Accepted Cycle 15 Observing Proposals

WD BINARES & CV

Proposal Number	Subject Category	PI Name	Type	Time (ks)	Title
15300309	WD BINARIES AND CV	Pooley	GO	50	Determining the Nature of an 18-minute UV source in NGC 1851
15300487	WD BINARIES AND CV	Montez	GO	60	Probing Shocks of the Young Planetary Nebula NGC 7027
15300552	WD BINARIES AND CV	Starrfield	TOO	85	A Fermi/LAT Trigger of Grating Observations of One Bright Nova in Outburst
15300607	WD BINARIES AND CV	Takei	GO	8	Spatial Diagnostics of Potential X-ray Remnants in Old Novae T Aur and DK Lac
15300811	WD BINARIES AND CV	Takei	GO	100	X-ray Diagnostics of Evolving Nova Remnant in GK Per
15300872	WD BINARIES AND CV	Nelson	TOO	100	Probing mass ejection in novae with high resolution X-ray spectroscopy

Subject Category: WD BINARIES AND CV

Proposal Number: 15300309

Title: Determining the Nature of an 18-minute UV source in NGC 1851

Type: GO Total Time (ks): 50

PI Name: David Pooley

We have recently discovered an 18-minute UV source in the globular cluster (GC) NGC 1851. The system is either a symbiotic binary (a cool evolved star and a white dwarf with an 18 min spin period) or a chance superposition of a red giant and a white-dwarf binary system. In the latter case, the 18 minute period would be either the spin period of a magnetic white dwarf in an intermediate polar cataclysmic variable or the orbital period of a double-degenerate AM CVn binary. A measurement of the X-ray luminosity would discriminate between these two scenarios. A previous Chandra observation yielded an ambiguous detection so we propose here for a deeper observation which will conclusively answers this question.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
05:14:06.70	-40:02:48.10	NGC 1851	ACIS-S	NONE	50

Subject Category: WD BINARIES AND CV

Proposal Number: 15300487

Title: Probing Shocks of the Young Planetary Nebula NGC 7027

Type: GO Total Time (ks): 60

PI Name: Rodolfo Montez

The rapid evolution of the planetary nebula NGC 7027 provides a rare glimpse at the evolution of the shocks. We propose a detailed spatial and spectroscopic study of the shock conditions in NGC 7027 that will enhance and bridge our understanding of the shocks seen in other planetary nebula. Comparison between the Cycle 1 observation and a new Cycle 15 observation will (i) confirm the presence of the two components in the extended X-ray emission, (ii) measure the changes (spatial and spectral) in the components, and, (iii) provide a valuable trove of tests and inputs for shock conditions and hydrodynamical simulations. We rely on the unprecedented spatial resolution and soft-sensitivity of Chandra.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
21:07:01.60	+42:14:10.20	NGC 7027	ACIS-S	NONE	60

Subject Category: WD BINARIES AND CV

Proposal Number: 15300552

Title: A Fermi/LAT Trigger of Grating Observations of One Bright Nova in Outburst

Type: TOO Total Time (ks): 85

PI Name: Sumner Starrfield

A new and perplexing result in 2012 was the discovery by the Fermi/LAT that two Classical Novae (Mon 2012 and Sco 2012) were emitting gamma-rays at E > 100 MeV. The cause of this VHE emission is currently not understood but X-ray grating observations early in the outburst should shed light on the cause. We propose to obtain 2 grating spectra with Chandra of one bright CN in outburst. Our target will be determined based on a detection by the Fermi/Large Area Telescope (LAT), a confirmation by ground-based spectroscopy that it is a CN, and a Swift/XRT determination that it is sufficiently bright for an HETG+ACIS-S grating observation. A second spectrum will be obtained with the LETG+HRC-S when the nova has transitioned into the Super Soft Source phase.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
		Nova ToO	ACIS-S	HETG	40
		Nova ToO	HRC-S	LETG	45

Subject Category: WD BINARIES AND CV

Proposal Number: 15300607

Title: Spatial Diagnostics of Potential X-ray Remnants in Old Novae T Aur and DK Lac

Type: GO Total Time (ks): 8

PI Name: Dai Takei

We propose 5 and 3 ks ACIS-S snapshots of potentially extended X-ray remnants of two old classical novae, T Aur and DK Lac. They are the likely counterparts of X-ray sources discovered in our Swift survey of old classical novae, and each target has a spatially-resolved optical remnant with a size of order arcseconds. The additional short Chandra snapshots will confirm or reject the tentative Swift identifications through pinpoint astrometry, and will distinguish between extended remnant emission or rejuvenated accretion. Both are important for understanding binary evolution and also potential post-outburst hibernation, while detection of extended emission will represent extremely rare additions to the exclusive club of X-ray emitting classical nova remnants.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
05:31:59.10	+30:26:45.00	T Aur	ACIS-S	NONE	5
22:49:46.90	+53:17:19.30	DK Lac	ACIS-S	NONE	3

Subject Category: WD BINARIES AND CV

Proposal Number: 15300811

Title: X-ray Diagnostics of Evolving Nova Remnant in GK Per

Type: GO Total Time (ks): 100

PI Name: Dai Takei

We propose a 100 ks ACIS-S observation of the old classical nova GK Per, which has a unique spatially well-resolved X-ray remnant. A Chandra observation 14 years ago discovered thermal and non-thermal signatures, similar to those found in supernova remnants. The goal of this program is to obtain second-epoch Chandra imaging spectroscopy to measure the X-ray proper motion of the expanding nebula and assess the ejecta velocity, mass, and energetics. In addition, comparison of the intensities of the non-thermal X-ray hot spots will probe the magnetic field strength and particle acceleration potential of this classical nova remnant. GK Per is the only nova remnant for which this study can be made, and the success of this program will provide an important clue to classical novae.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
03:31:11.80	+43:54:16.80	GK Per	ACIS-S	NONE	100

Subject Category: WD BINARIES AND CV

Proposal Number: 15300872

Title: Probing mass ejection in novae with high resolution X-ray spectroscopy

Type: TOO Total Time (ks): 100

PI Name: Thomas Nelson

We request a Chandra target of opportunity observation of the next bright nova discovered in outburst that is visible to the Very Large array radio observatory. The resulting high resolution X-ray spectra will be used in conjunction with detailed multiwavelength light curves, especially in the radio regime, to study the mass ejection process in novae. We will utilize detailed modeling of absorption of the central source by shells of hot, photoionized gas to characterize the nova ejecta in X-rays, and then compare this to the mass ejection implied by radio light curves. The two regimes in tandem will enable us to estimate the mass ejected during outburst.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
		A bright nova	HRC-S	LETG	100

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