NuSTAR Bringing the High Energy Universe into Focus

 

Legacy Surveys

NuSTAR will continue both Galactic and Extragalactic Legacy Surveys during the extended mission with programs selected based on community input. The legacy surveys listed below have been chosen to be observed during the extended mission (2015-2018).

Last updated: 2017/07/19


Why Legacy Surveys?

Two of NuSTAR’s key mission goals based on which the mission was selected were to conduct deep, wide-field surveys in both Galactic and extragalactic fields. While a significant amount of time has already been invested in these surveys during the baseline mission, it is clear that maximizing the legacy of the NuSTAR satellite will require significantly extending both of these surveys.


Legacy Surveys in Action

The Legacy Survey programs have been designed in consultation with the community. The detailed observations are planned, scheduled, and executed by the NuSTAR science team. This team has the expertise and the experience in the intricacies of such observations – e.g., avoiding stray light from (transient) bright sources, scheduling repeat observations to minimize roll angle changes, optimal background subtraction, and source identification. Such data will have no exclusive use period and will be obtained by the NuSTAR science team as a service to the community. The NuSTAR team, with its extensive experience with background subtraction and source identification that are specific to the NuSTAR instrument, will also provide high level data products (such as source positions and spectra in electronic form) for the community’s use.


The Extragalactic Survey

One of the principal goals of the NuSTAR extragalactic surveys is to constrain the high-energy X-ray luminosity function and trace its evolution as a function of redshift and AGN obscuration. We will continue to pursue a multi-layer survey strategy, adding ultra-deep observations within the current deep fields (e.g., ECDFS, EGS, and COSMOS), expanding the number of deep fields (e.g., adding fields such as GOODS-N), and increasing the area of shallow observations through serendipitous sources and potentially a wider-area, shallow survey (e.g., mapping fields such as Stripe 82, XBoötes, and/or the eROSITA deep polar fields). Besides the science afforded by studies of samples of individual sources, such data, with a focus on improving statistics at the least well-constrained portions of L-z space, will significantly improve our understanding of the full census of AGN, the cosmic history of black hole growth, and the role of AGN feedback in galaxy evolution.

There are three survey fields and four samples of AGN approved for observations in 2017 and 2018 in addition to the continuation of the Swift-BAT AGN survey. 

       1)   Deeper exposures around sources discovered in three sky surveys, XMMLSS, XBootes, and SDSS stripe 82.   50 ks exposures for each position are planned for 2017-2018 (Total 1650 ks)

ObsID Name J2000 (deg)
RA Dec
60364001 XMMLSS_001   (1) 34.592333 -5.103950
60364002 XMMLSS_002 35.067750 -4.078042
60364003 XMMLSS_003 34.912833 -5.192706
60364004 XMMLSS_004 35.741583 -4.311372
60364005 XMMLSS_005   (1) 34.454208 -5.385211
60364006 XMMLSS_006 36.457375 -4.006881
60365001 XBootes_001  * 218.934000 35.076178
60365002 XBootes_002 216.189500 33.244019
60365003 XBootes_003 216.348750 35.473378
60365004 XBootes_004 217.551875 33.244361
60365005 XBootes_005  * 217.841083 34.679581
60365006 XBootes_006 217.448583 35.574303
60366001 S82X_001  (2) 43.800917 -0.183547
60366002 S82X_002  * 352.614000 -0.683503
60366003 S82X_003 351.926917 -0.754672
60366004 S82X_004 334.374542 0.818278
60366005 S82X_005 25.624042 -0.598903
60366006 S82X_006 20.000708 -0.371197
60366007 S82X_007 19.128708 0.451014
60366008 S82X_008 18.387708 0.496672
60366009 S82X_009 18.157958 0.086319
60366010 S82X_010 16.595375 -0.355475
60366011 S82X_011 16.528833 0.340319
60366012 S82X_012 16.153333 -0.297100
60366013 S82X_013 13.859375 0.605947
60366014 S82X_014  * 46.175292 -1.053886
60366015 S82X_015  * 54.075375 0.542350
60366016 S82X_016 24.925583 -0.105264
60366017 S82X_017 20.922750 0.743306
60366018 S82X_018 13.870125 0.581256
60366019 S82X_019 352.343625 -0.928497
60366020 S82X_020 353.071958 0.277431
60366021 S82X_021 353.071833 0.278039
 
* Observation Completed  
(1) Observation postponed, overlap with UDS fields  
(2) Observation postponed. May be observed in NuSTAR GO cycle-3 (proposal 03040).
 
       2)  Longer exposures for a sample of AGN previously observed in Swift-BAT detected AGN sample were added for observations in 2016-2017 (total 370 ks)
 
ObsID Name J2000 (deg) Exposure
RA Dec (ks)
60261001 NGC 6300  * 259.246674 -62.819721 2 x 20
60261002 ESO 383-18  * 203.359589 -34.016308 100
60261003 3C 105  * 61.818539 3.70719 2 x 20
60261004 3C 452  * 341.45459 39.6875 40
60261005 NGC 7319 (Stephan's Quintet) 339.0149158 33.975858 50
60261006 NGC 7130  * 327.0813329 -34.9512439 50
60261007 IC 1663  * 18.52858 -32.650829 50

* Observation Completed

       3)  Dual Swift-BAT detected AGN coordinated with XMM-Newton cycle-16 proposal 080220 (PI Koss) (total 140 ks)

 
ObsID Name J2000 (deg) Exposure
RA Dec (ks)
60363001 6dFJ1254564m265702  * 193.73480000 -26.95050000 20
60363002 AM0224m283  * 36.60810000 -28.35030000 20
60363003 2MASXJ02420381p0510061  * 40.51580000 5.16840000 20
60363004 IRAS05589p2828 90.5446 28.4717 20
60363005 1RXSJ213445d2m272551  * 323.6875 -27.430872 20
60363006 Mrk248 198.821937 44.407105 20
60363008 UGC_06081 165.074965 10.049089 20

* Observation Completed

 

       4)  Deeper exposures of Swift-BAT detected Seyfert type-1 AGN   (total 350 ks)

 
ObsID Name J2000 (deg) Exposure
RA Dec (ks)
60376001 2MASXJ19301380p3410495 292.557500 34.180500 50
60376002 Mrk463 209.011749 18.371469 50
60376003 1RXSJ034704d9m302409 56.772099 -30.3978 50
60376004 SDSSJ104326d47p110524d2 160.860300 11.090100 50
60376005 Mrk1393 227.224800 -0.197000 50
60376006 3C309d1 224.781600 71.672200 50
60376007 UGC06728 176.316800 79.681500 50

* Observation Completed

      5)  Swift-BAT detected AGN (20 ks each)

Observations of extragalactic sources taken from the Swift BAT 70-month hard X-ray survey will continue in 2017-2018. Each target will be observed for 20 ks by NuSTAR and 7 ks by Swift-XRT. On average 6 sources are observed each month.

      6)  NuLANDSRepresentative IRAS-selected AGN sample (total 990 ks)

The distribution of obscuring column densities is a key observational boundary condition for models of AGN evolution and the cosmic X-ray background. The NuSTAR Local AGN N_H Distribution Survey (NuLANDS) will observe a representative sample of 30 IRAS-selected AGN hosts at z<~0.04 to study their gas column densities, and to understand the AGN-galaxy connection.

Each target will also be contemporaneously observed by Swift to obtain 7 ks XRT exposures.

ObsID Name J2000 (deg) Exposure
RA Dec (ks)
60360002 NGC 0449 19.0300485 33.0893489 30
60360003 IC 4995 304.995765 -52.621908 30
60360004 UGC 01214 25.990757 2.349857 30
60360005 2MASX J01500266-0725482 27.5112236 -7.4301471 30
60360006 Mrk 1239 148.0795705 -1.6120791 20
60360007 KUG 0312+013 48.7722605 1.5083828 30
60360008 SDSS J152132.21+391206.9 230.3874232 39.2007671 20
60360009 FAIRALL 0265 104.1241396 -65.5604616 20
60360010 MCG-02-08-039 45.1276199 -11.4158391 30
60361011 2MASXJ 15504152-0353175 237.6729079 -3.8883412 40
60361012 CGCG 498-038 358.9343387 30.2123336 40
60361013 UGC 10120 239.7901018 35.0298614 25
60361014 IC 1198  * 242.151567 12.3310191 25
60361015 MRK 0315 346.0109554 22.6242896 25
60361016 KUG 1021+675 156.304361 67.2971854 40
60361017 ESO 344-G016  * 333.6750623 -38.8063487 25
60361018 KUG 0135-131 24.5224744 -12.8695399 40
60361019 CGCG 004-040 127.5600721 -2.8805107 40
60361020 FGC 0061 8.6812072 -0.0407954 40
60361021 SBS 1426+573 217.0749075 57.1718086 40
60361022 2MASX J03241196-5750116 51.0498478 -57.8367233 40
60361023 UGC 09944  * 233.9486961 73.450724 30
60362024 CGCG 166-047 235.9888601 28.5239359 40 #
60362025 2MASX J21391374-2646315  * 324.8071404 -26.7754607 40 #
60362026 2MASX J03381036+0114178 54.5432269 1.238402 40 #
60362027 2MASX J02560264-1629159 44.0110223 -16.4876579 40 #
60362028 CGCG 077-080 230.2218089 8.3968659 40 #
60362029 ESO 018-G009 126.0329349 -77.7825942 30 #
60362030 IRAS 03362-1641 54.6398049 -16.5384568 40 #

* Observation completed

# Will be coordinated with XMM-Newton cycle-16 priority C observation (proposal 080515, PI Boorman)


The Galactic and Nearby Galaxies Survey

NuSTAR is allowing us to probe more deeply into the Galaxy than ever before. The goals of these surveys are to expose the hidden Milky Way and reveal the wide range of astrophysics that creates high-energy emission. NuSTAR studies of flares from Sgr A* probing the physical conditions in the immediate vicinity of the nearest supermassive black hole. By studying high-mass X-ray binaries (HMXB) in a range of environments, we can learn about their formation soon after a supernova event and determine the fraction of HMXBs with black holes. The latter is important for answering questions about HMXB evolution, such as how many neutron star/black hole binaries exist, which has important implications for future gravity wave experiments. In addition to point source studies, NuSTAR is also investigating diffuse emission toward the Galactic Center, including the Galactic ridge emission and the time variation of the reflected emission from dense molecular clouds that probe the accretion history of Sgr A*. The coordinates and characteristics of any transient discovered will immediately be broadcast to the community via electronic circulars such as the Astronomer’s Telegram.

There are seven survey programs approved for observations in 2017 and 2018:

1) Survey of hard X-ray sources in M33 (3 positions, 200 ks each, total 600 ks)

A NuSTAR survey of M33 will be conducted to study the distribution of X-ray binary (XRB) accretion states in an actively star-forming environment, and constrain the 3-40 keV spectrum of the most luminous XRB in the Local Group, M33 X-8. Three 100 ks NuSTAR exposures will be obtained over an area covering ~70% of the star-formation activity within the M33 disk in 2017 and an additional three 100 ks exposures will be obtained in the summer of 2017 coordinated with XMM-Newton cycle-16 observations (proposal 080035, PI Lehmer).

The goal is to characterize XRB accretion states for ~15 sources, most of which are expected to be high-mass XRBs (HMXBs). By comparison, the number of visible Milky Way and Magellanic Cloud HMXBs above the luminosity limit of this survey (LX ~ 1037 erg/s) is ~6 (depending on variability). In addition, this data set will contain a factor of 8-15 times more HMXBs than the NuSTAR survey of M31. Taken together, these observations will provide a significant improvement in our knowledge of HMXB accretion states that will prove valuable for theoretical XRB population synthesis studies.

2) Hard X-ray observations of sources identified in Swift Galactic Plane Survey Key Project (Multiple targets, 500 ks total)

ObsID

Name

J2000 (deg)

Exposure

RA

Dec

(ks)

30360001

Swift J1843.5-0343  *

280.89481

-3.71571

75

* Observation Completed

3) Survey of hard X-ray sources in the SMC (3 positions, 250 ks each, total 750 ks)

A NuSTAR survey of three fields in the SMC will be conducted in 2017. Observations of each position will be 150 + 100 ks separated by at least two months to examine variability of sources in each field of view.

4) SMC transients  - followup of targets detected during the Swift SMC Survey (S-CUBED) (Multiple targets, 200 ks total)

ObsID

Name

J2000 (deg)

Exposure

RA

Dec

(ks)

30361001

SXP_59d0  *

13.7340833

-72.4466389

50

* Observation Completed

5) Sgr A molecular clouds (300 ks)

ObsID

Name

J2000 (deg)

Exposure

RA

Dec

(ks)

40113001

Sgr A Molecular Cloud

266.4747

-28.9013

2 x 150 *

*First of two observations was performed in 2016 October

6) Sgr A* monitoring (350 ks)  

Coordinated with Chandra/Spitzer cycle-18 proposal 18620763 (PI Baganoff, 2 x 24 hour duration observations in the summer of 2017) and with Chandra GTO proposal 18620742 (PI Garmire) coordinated with the Event Horizon Telescope in the spring of 2017. Further observations will also be performed in 2018 coordinated with Chandra cycle-19 programs.

7) TeV gamma-ray source survey (450 ks)

ObsID

Name

J2000 (deg)

Exposure

RA

Dec

(ks)

30362001

HESS J0632+057

98.240

5.810

100

 

30362002

2HWC J1928+178  *

292.178333

17.774167

100

 

30362003

DA 495  (1)

298.070

29.430

150

 

30362004
30362005

2HWC J1927+187  (2)

291.85979
291.86534

18.96105
18.70740

50
50

* Observation completed
(1) 50ks completed so far
(2) Observations postponed


Cosmic X-ray Background (CXB)  (200 ks)

The cosmic X-ray background (CXB) was discovered over 50 years ago, and represents an important integral of the total accretion power of supermassive black holes. However, despite many attempts to measure its spectrum, the normalization of the spectrum at ~3-20keV has considerable uncertainty. In this legacy survey we plan to use the Moon as a shutter, enabling a clear and unambiguous measurement of the CXB to be made with NuSTAR. During the observation we will track the Moon while it oscillates, due to parallax, over 4 degrees of sky. An exposure of 200ks is sufficient to achieve our goal of measuring the normalization and spectral shape of the CXB.


Get Involved!

Interested in providing feedback about the Legacy Surveys? We are now activiely soliciting input from the community. Please give us your thoughts!