Chandra Large and Very Large Projects

Proposal Number: 02600758

Title: THE X-RAY POINT SOURCE POPULATION IN SPIRAL GALAXIES

PI Name: Andrea Prestwich

Emission from discrete sources dominates the X-ray luminosity in spiral galaxies. We propose to survey a sample of nearby spiral galaxies to characterise the properties of the discrete sources. We have chosen nearby, face-on galaxies which span the Hubble sequence for spirals. Chandra's superb imaging capability will allow us to detect sources down to a luminosity of 4e36 erg s^-1 in the ROSAT band. We aim to classify souces as accretion powered binaries (Low or High Mass) or supernova remnants. Our survey will go more than a factor of 20 deeper than the deepest ROSAT pointings of the same galaxies. This data will enable us to look for trends in the characteristics of discrete sources with Hubble type, metallicity and stellar population.

Proposal Number: 03600940

Title: MONITORING THE EXTREME X-RAY FLARING OF SAGITTARIUS A* AND A DEEP SURVEY OF THE CENTRAL 40 PC OF THE GALAXY

PI Name: Frederick Baganoff

In Cycle 1, we discovered the first clear evidence of X-ray emission from Sgr A*, the compact radio source associated with the massive black hole (MBH) at the dynamical center of the Milky Way. In Cycle 2, we made the first detection of rapid, large-amplitude X-ray variability of Sgr A*. To gather unprecedented information about the immediate environment of an MBH, we propose a 510-ks ACIS-I observation of Sgr A* to measure the quiescent-state emission spectrum and to characterize the timescales, duty cycle, energetics, and spectral evolution of the flares. Simultaneous monitoring with OVRO and VLBA are being proposed to search for correlated variations and lags predicted by theory to characterize the flaring state emission process. We will also obtain a deep survey in this rich field.

Proposal Number: 05600587

Title: An Ultra-Deep Study of M101

PI Name: Kip Kuntz

We propose a multi-segmented 1 Ms observation of M101, a near-by face-on spiral in a direction of low Galactic absorption. The observation will detect point sources to L(0.5-2.0 keV)=4x10^35 ergs/s, detect nearly all young to middle-aged SNR, detect and resolve super-bubbles typical of the Milky Way, and provide an unprecedented view of the hot ISM in a spiral galaxy. Coupled with our HST-ACS images, we will be able to measure directly the X-ray output of individual stellar clusters, and better determine the galactic energy budget. The resulting images will bring a wealth of material to a broad range of galactic, stellar, and ISM studies.

Proposal Number: 07610889

Title: The Chandra ACIS Survey of M33 (ChASeM33): A Deep Survey of the Nearest Face-on Spiral Galaxy

PI Name: Manami Sasaki

We propose to study the overall `ecology' of spiral galaxies - the diffuse ISM and the compact sources within - through a survey of M33, the closest face-on spiral. Our ACIS-I survey will cover the central region of M33 with a sensitivity of 5.E34 erg/s for point sources and 1.E35 erg/s for diffuse ones, at least a factor of two deeper than existing XMM data. More importantly, Chandra's superior spatial resolution will give a detailed view of complex structures (superbubbles, supernova remnants, and truly diffuse hot gas) on all scales > 10 pc, will resolve source confusion that confounds previous studies, and will enable identification of most point sources. The rich data set from the M33 survey, together with what promises to be an iconic image, ought to be part of Chandra's legacy.

Proposal Number: 07620395

Title: A Chandra legacy program: deep study of LMXB populations

PI Name: Giuseppina Fabbiano

LMXBs are the only direct fossil evidence of the formation and evolution of binary stars in elliptical galaxies. To understand LMXB formation and evolution, and address the role of globular clusters (GC) in these processes, we propose a 1,245Ks ACIS-S program to study LMXB populations of elliptical galaxies, to limiting luminosities well in the range of normal neutron star binaries. We will study, and compare with models, the spatial distributions and spectral properties of these sources. We will derive, and compare with population synthesis models, their low-luminosity XLFs. Our monitoring approach will constrain the fraction of transients, thus placing important limits on formation mechanisms, binary evolution and disk outburst theory.

Proposal Number: 08620985

Title: Massive Star Formation and Energy Feedback in the Starburst Region N11

PI Name: You-Hua Chu

The starburst region N11 is the second largest star formation complex in the LMC. It contains four OB associations distributed in a central superbubble and dense HII regions along its periphery, indicating sequential star formation. Spitzer observations have revealed hundreds of massive protostars in N11. The relatively simple structure of N11 makes it an ideal starburst region for detailed study. We request a 300 ks ACIS-I observation of N11 to determine the X-ray properties of point sources and diffuse emission at arcsecond resolution. This deep observation will allow us to study (1) discrete X-ray source population and empirical L_x/L_bol, (2) X-ray emission from protostars, (3) bubbles/superbubbles and stellar energy feedback, and (4) physical structure of a starburst region.

Proposal Number: 09620513

Title: Galaxies across the Octaves: A Chandra Legacy Survey of SINGS Galaxies

PI Name: Leigh Jenkins

We propose to complete a rich, X-ray unbiased, multiwavelength Legacy dataset for a sample of 40 nearby galaxies. These galaxies are a distance limited (d < 10 Mpc) sample from the Spitzer Infrared Nearby Galaxy Survey (SINGS) Legacy program. The sample is now 45% complete. Our observations will detect X-ray binaries as faint as 3e36-1e37 erg/s, allowing us to constrain the X-ray binary/SFR correlation over a large range of galaxy properties and build X-ray binary Luminosity Functions for galaxies across a range of star formation histories. We will produce Legacy datasets and source catalogs for the community, and run theoretical binary population synthesis models in support of this effort.

Proposal Number: 10610785

Title: Wide, deep and sharp: A comprehensive observation of M82, the exemplar of starburst activity

PI Name: David Strickland

We propose to observe M82, the exemplar of starburst and superwind activity, with a mosaic of deep ACIS-S observations that will cover the starburst region, the galactic disk and much of the extended superwind. The region of highest resolution (FWHM < 1.5") will cover the same field of view as recent deep HST and Spitzer observations. It will be the most data-rich X-ray study of a starburst galaxy ever (>1E6 counts), and will greatly advance our knowledge of the soft X-ray-emitting gas in the superwind, the very hot metal-enriched plasma within the starburst region, and the the X-ray point source population in both the starburst region and the galactic disk. It will further complement the investment made in observing M82 by the other Great Observatories, Hubble and Spitzer.

Proposal Number: 11620601

Title: Ultra-Luminous x-Ray Sources in the Most Metal-Poor Galaxies

PI Name: Andrea Prestwich

There is growing observational and theoretical evidence to suggest that Ultra-Luminous X-ray sources (ULX) form preferentially in low metallicity environments. Here we propose a survey of 27 nearby (< 30Mpc) star-forming Extremely Metal Poor Galaxies (Z<5% solar). There are almost no X-ray observations of such low abundance galaxies (3 in the Chandra archive). These are the most metal-deficient galaxies known, and a logical place to find ULX if they favor metal-poor systems. We plan to test recent population synthesis models which predict that ULX should be very numerous in metal-poor galaxies. We will also test the hypothesis that ULX form in massive young star clusters, and ask for HST time to obtain the necessay imaging data.

Proposal Number: 11620915

Title: Accretion onto nuclear black holes in early type galaxies: comparing field vs. clusters

PI Name: Elena Gallo

IF black holes are indeed ubiquitous in galactic nuclei, little is known about the frequency and intensity of their activity, the more so at the low-mass/low-luminosity end. Our cycle 8 observations of the Virgo clusters have delivered the most comprehensive measurement of the duty cycle, showing that although black holes are present even in low mass spheroids, activity is a strong function of mass. However, nuclear activity is also expected to be a strong function of environment, which regulates the gas supply through processes such as ram pressure stripping and merging. We propose the first systematic study of the effects of the environment on low level accretion, by combining our Virgo study with new observations and archival data of a volume limited sample of 100 field spheroids.