Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

19549 results found.

  1. LIGO/Virgo G298048: AST3-2 observations of SSS17a/DLT17ck from Antarctica
  2. LIGO/Virgo G298048: ATCA monitoring of SSS17a in NGC 4993
  3. GRB 170912B: Swift/UVOT Upper Limits
  4. GRB 170912A: Swift-XRT refined Analysis
  5. LIGO/Virgo G299232: Khureltogot observations
  6. GRB 170912A: Swift/UVOT Upper-Limits
  7. GRB 170912B: Enhanced Swift-XRT position
  8. LIGO/Virgo G299232: Pierre Auger Observatory follow-up
  9. LIGO/Virgo G298389: Pierre Auger Observatory neutrino follow-up
  10. GRB 170912B: Swift detection of a burst
  11. GRB 170912A: Enhanced Swift-XRT position
  12. GRB 170912A: Swift detection of a burst
  13. LIGO/Virgo G298048: VLBA upper limits at 8.7GHz for the GW counterpart SSS17a/DLT17ck on August 20-21 UT
  14. GRB 170906A: Swift/UVOT Detection
  15. GRB 170906B: Swift/UVOT Upper Limits
  16. LIGO/Virgo G299232: Swift-XRT sources
  17. GRB 170906C: optical observations
  18. GRB 170906C: COATLI Observations
  19. GRB 170906C: Swift/UVOT Upper Limits
  20. GRB 170906C: Enhanced Swift-XRT position
  21. GRB 170906C: Swift-XRT observations
  22. GRB 170906A: REM optical/NIR observations
  23. GRB 170906A: Enhanced Swift-XRT position
  24. GRB 170906B: Enhanced Swift-XRT position
  25. GRB 170906B: Swift detection of a burst
  26. GRB 170906A: Swift detection of a burst with an optical afterglow
  27. IPN Triangulation of GRB 170904A (long/very bright)
  28. LIGO/VIRGO G298048: Radio detection of SSS17a at 6 GHz with the VLA
  29. LIGO/VIRGO G298048: Radio detection of SSS17a at 3GHz with the VLA/JAGWAR
  30. LIGO/Virgo G299232: Maidanak observations of optical transient SwiftJ014008.5+343403.6
  31. LIGO/Virgo G299232: LOFAR follow-up
  32. GRB 170827A: LCO Observations
  33. GRB 170903A: Swift/UVOT Upper Limits
  34. GRB 170903A: UAFO /ISON optical upper limit
  35. LIGO/Virgo G298048: e-MERLIN upper limits on 5 GHz compact emission from SSS17a
  36. LIGO/Virgo G298048: ATCA monitoring of SSS17a in NGC 4993
  37. LIGO/Virgo G299232: RoboPol observations of MASTER OT J033744.97+723159.0
  38. GRB 170903A: MITSuME Okayama upper limits
  39. GRB 170903A: Host galaxy redshift from OSIRIS/GTC
  40. LIGO/Virgo G298048: Chandra X-ray Update on GW170817
  41. GRB 170903A: Enhanced Swift-XRT position
  42. GRB 170903A: Nanshan optical upper limit
  43. GRB 170903A: Swift-XRT observations
  44. Swift Triggers on MAXI J1535-571
  45. GRB 170902A: Enhanced Swift-XRT position
  46. LIGO/Virgo G297595: DECam observations of BBH merger region of interest
  47. GRB 170902A: Swift detection of a burst or possible Galactic transient
  48. LIGO/Virgo G298048: Chandra monitoring of the X-ray emission from SSS17a
  49. LIGO/Virgo G298048: Continued X-ray monitoring and X-ray detection of GW170817 [erratum]]
  50. LIGO/Virgo G298048
  51. LIGO/Virgo G298048: Hubble Space Telescope observations
  52. LIGO/Virgo G299232: GRAWITA Asiago optical observations
  53. LIGO/Virgo G299232: continued WHT observations of the field of SwiftJ014008.5+343403.6
  54. LIGO/Virgo G298048: Discovery of X-ray emission from SSS17a in NGC4993
  55. GRB 170830A: iTelescope optical observations
  56. LIGO/Virgo G299232: HAWC follow-up
  57. LIGO/Virgo G299232 : RATIR Optical and NIR Observations of Swift UVOT source
  58. LIGO/Virgo G299232: WHT non-detection u-band optical transient
  59. LIGO/Virgo G299232: Liverpool Telescope observations
  60. LIGO/Virgo G299232: observations of the optical Transient Discovered by Swift/UVOT
  61. IPN Triangulation of GRB 170826B
  62. LIGO/Virgo G299232: PIRATE observations of MASTER OT J033744.97+723159.0
  63. LIGO/Virgo G299232/PGWB170825.55: early MASTER observations of the Swift UVOT source position
  64. LIGO/Virgo G298048: ALMA observations
  65. LIGO/Virgo G299232: GRAWITA Asiago/Copernico Telescope observations
  66. GRB170827A: Further GROND follow-up observations
  67. LIGO/Virgo G299232: COATLI Observations of MASTER OT J033744.97+723159.0
  68. IPN Triangulation of GRB 170827B (short)
  69. LIGO/Virgo G298936: HAWC follow-up
  70. GROND observations of GRB170827A
  71. GRB 170827A: ePESSTO NTT afterglow candidate
  72. GRB 170823A: TAROT Calern observatory optical observations
  73. LIGO/Virgo G299232: OVRO-LWA simultaneous low frequency radio observations of localization region
  74. LIGO/Virgo G299232: LOFAR follow-up
  75. GRB 170827A: Swift/UVOT Upper Limits
  76. GRB 170827A: REM optical/NIR observations
  77. GRB 170827A: Swift detection of a burst
  78. LIGO/Virgo G299232: CALET Observations
  79. LIGO/VIRGO G299232: Fermi GBM Observations
  80. LIGO/Virgo G299232 : Fermi-LAT search for high-energy gamma-ray counterpart
  81. LIGO/Virgo G298389: HAWC follow-up
  82. LIGO/Virgo G298936: CALET Observations
  83. GRB 170820A CALET Gamma-Ray Burst Monitor detection
  84. LIGO/Virgo G299232: Swift/BAT data search
  85. LIGO/Virgo G299232: INTEGRAL search for a prompt gamma-ray counterpart
  86. LIGO/Virgo G296853: VLT observations by GLGW Hunters
  87. LIGO/Virgo G299232 ANTARES search
  88. LIGO/Virgo G297595: INTEGRAL pointed follow-up observations
  89. LIGO/Virgo G297595: Gemini and VLT observations by GLGW Hunters
  90. LIGO/Virgo G298936 TAROT/TZAC observations
  91. LIGO/Virgo G298936 : MAXI/GSC observations
  92. LIGO/Virgo G298048: MASTER Global-Net early optical observations and the Possible KiloNova SSS17a in NGC 4993 photometry and merging rate
  93. LIGO/Virgo G298048: Pierre Auger Observatory neutrino follow-up
  94. LIGO/Virgo G298048: HAWC follow-up
  95. LIGO/Virgo G298048: Gemini-South Imaging and Spectroscopy
  96. LIGO/Virgo G298048: MUSE Integral Field Observations
  97. LIGO/Virgo G298048: LOFAR follow-up
  98. LIGO/Virgo G297595: H.E.S.S. very-high energy gamma-ray follow-up
  99. LIGO/Virgo G298048: INTEGRAL pointed follow-up observations
  100. LIGO/Virgo G298048: Results of the ASKAP search for fast radio bursts

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov