Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

28303 results found.

  1. GRB 170921A: NOT optical observations
  2. GRB 170921A: Nanshan optical upper limit
  3. GRB 170921A: Enhanced Swift-XRT position
  4. GRB 170921A: MITSuME Okayama upper limits
  5. GRB 170921A: Swift-XRT refined Analysis
  6. GRB 170921A: TAROT Calern observatory optical observations
  7. GRB 170921B: Fermi GBM detection
  8. GRB 170921A: Swift detection of a burst
  9. LIGO/Virgo G298048: ATCA monitoring of SSS17a in NGC 4993
  10. LIGO/Virgo G298048: Limits from an FRB search of SSS17a with the Parkes 64m Radio Telescope
  11. LIGO/Virgo G298048: Milliarcsecond imaging of the NGC 4993 central radio source
  12. LIGO/Virgo G298048: ATLAS pre-discovery limits 601 to 16 days before first detection of SSS17a/DLT17ck
  13. LIGO/Virgo G298048: ATCA monitoring of SSS17a in NGC 4993
  14. GRB 170912B: Swift/UVOT Upper Limits
  15. GRB 170912B: Swift-BAT refined analysis
  16. GRB 170912A: Swift-BAT refined analysis
  17. GRB 170912A: Swift-XRT refined Analysis
  18. LIGO/Virgo G299232: Khureltogot observations
  19. GRB 170912A: Swift/UVOT Upper-Limits
  20. GRB 170912B: Swift-XRT refined Analysis
  21. GRB 170912B: Fermi GBM observations
  22. LIGO/Virgo G298936: Konus-Wind observations
  23. LIGO/Virgo G299232: Konus-Wind observations
  24. GRB 170911A: Fermi GBM observation
  25. GRB 170912B: Enhanced Swift-XRT position
  26. LIGO/Virgo G299232: Pierre Auger Observatory follow-up
  27. LIGO/Virgo G298389: Pierre Auger Observatory neutrino follow-up
  28. GRB 170912B: Swift detection of a burst
  29. GRB 170912A: Enhanced Swift-XRT position
  30. GRB 170912A: Swift detection of a burst
  31. GRB 170911A: MAXI/GSC detection
  32. LIGO/Virgo G298048: VLBA upper limits at 8.7GHz for the GW counterpart SSS17a/DLT17ck on August 20-21 UT
  33. LIGO/Virgo G298048: LWA Detection
  34. GRB 170906A: Swift/UVOT Detection
  35. GRB 170906B: Swift/UVOT Upper Limits
  36. GRB 170906B: Swift-XRT refined Analysis
  37. LIGO/Virgo G299232: Swift-XRT sources
  38. GRB 170906C: optical observations
  39. GRB 170906B: Fermi GBM detection
  40. GRB 170906A: Fermi GBM detection
  41. GRB 170906A: Swift-BAT refined analysis
  42. GRB 170906C: COATLI Observations
  43. GRB 170906A: Swift-XRT refined Analysis
  44. GRB 170906C: Swift/UVOT Upper Limits
  45. GRB 170906C: Swift-XRT refined Analysis
  46. LIGO/Virgo G298048 GRAWITA: VST-ESO PARANAL follow up of SSS17a in NGC4993.
  47. GRB 170906C: Swift-BAT refined analysis
  48. GRB 170906C: Enhanced Swift-XRT position
  49. GRB 170906A: MASTER-OAFA (Argentina) early automatic OT detection
  50. GRB 170906C: Swift-XRT observations
  51. GRB 170906A: REM optical/NIR observations
  52. GRB 170906A: Enhanced Swift-XRT position
  53. GRB 170906B: Enhanced Swift-XRT position
  54. GRB 170906B: Swift detection of a burst
  55. GRB 170906A: Swift detection of a burst with an optical afterglow
  56. IPN Triangulation of GRB 170904A (long/very bright)
  57. GRB 170901B: Insight-HXMT detection
  58. GRB 170904A: Insight-HXMT detection
  59. LIGO/VIRGO G298048: Radio detection of SSS17a at 6 GHz with the VLA
  60. GRB 170903A: Fermi GBM observation
  61. LIGO/Virgo G299232: Maidanak observations of optical transient SwiftJ014008.5+343403.6
  62. LIGO/Virgo G299232: LOFAR follow-up
  63. GRB 170827A: LCO Observations
  64. GRB 170903A: Swift/UVOT Upper Limits
  65. GRB 170903A: UAFO /ISON optical upper limit
  66. LIGO/Virgo G298048: e-MERLIN upper limits on 5 GHz compact emission from SSS17a
  67. LIGO/Virgo G298048: ATCA monitoring of SSS17a in NGC 4993
  68. LIGO/Virgo G299232: RoboPol observations of MASTER OT J033744.97+723159.0
  69. GRB 170903A: MITSuME Okayama upper limits
  70. GRB 170903A: Swift-XRT refined Analysis
  71. GRB 170903A: Host galaxy redshift from OSIRIS/GTC
  72. LIGO/Virgo G298048: Chandra X-ray Update on GW170817
  73. GRB 170903A: Enhanced Swift-XRT position
  74. GRB 170903A: Swift-BAT refined analysis
  75. GRB 170903A: Nanshan optical upper limit
  76. GRB 170903A: Swift-XRT observations
  77. Swift Triggers on MAXI J1535-571
  78. GRB 170902A: Enhanced Swift-XRT position
  79. LIGO/Virgo G297595: DECam observations of BBH merger region of interest
  80. GRB 170902A: Swift detection of a burst or possible Galactic transient
  81. LIGO/Virgo G298048: Chandra monitoring of the X-ray emission from SSS17a
  82. LIGO/Virgo G298048: Continued X-ray monitoring and X-ray detection of GW170817 [erratum]]
  83. LIGO/Virgo G298048: AGILE-GRID analysis of data contemporary to X-ray emission from SSS17a in NGC4993
  84. LIGO/Virgo G298048
  85. LIGO/Virgo G299232/PGWB170825.55: MASTER archive images of the SIWFT/UVOT and MASTER OT J033744.97+723159.0 in NGC1343 galaxy before 25
  86. LIGO/Virgo G298048: Hubble Space Telescope observations
  87. GRB 170831A: Fermi GBM detection
  88. GRB 170830A: Fermi GBM observation
  89. LIGO/Virgo G299232: GRAWITA Asiago optical observations
  90. LIGO/Virgo G299232: continued WHT observations of the field of SwiftJ014008.5+343403.6
  91. LIGO/Virgo G299232 ANTARES search (2)
  92. LIGO/Virgo G299232: GRAWITA Campo Imperatore optical observations
  93. LIGO/Virgo G298048: Discovery of X-ray emission from SSS17a in NGC4993
  94. GRB 170830A: iTelescope optical observations
  95. GRB 170830A: MAXI/GSC detection
  96. LIGO/Virgo G299232: HAWC follow-up
  97. LIGO/Virgo G299232 : RATIR Optical and NIR Observations of Swift UVOT source
  98. LIGO/Virgo G299232: WHT non-detection u-band optical transient
  99. LIGO/Virgo G299232: Liverpool Telescope observations
  100. LIGO/Virgo G299232: observations of the optical Transient Discovered by Swift/UVOT

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov