Skip to main content
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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"

2900 results found.

  1. Fermi GRB 200919C: Global MASTER-Net observations report
  2. Fermi GRB 200919B: Global MASTER-Net observations report
  3. IceCube-200916A: Two Candidate Counterparts from the Zwicky Transient Facility
  4. IPN triangulation of GRB 200916B (short)
  5. IceCube Alert 200914.00: Global MASTER-Net observations report
  6. IPN triangulation of GRB 200907A (short)
  7. Fermi GRB 200908A: Global MASTER-Net observations report
  8. Fermi GRB 200907C: Global MASTER-Net observations report
  9. GRB 200906A: Nanshan/NEXT optical upper limit
  10. Fermi GRB 200903B: Global MASTER-Net observations report
  11. GRB 200901A: Fermi GBM observation
  12. GRB 200901A: Swift detection of a burst
  13. GRB 200829A: Koshka Zeiss-1000 optical observations
  14. Fermi trigger No 620402299: Global MASTER-Net observations report
  15. Zwicky Transient Facility discovery of ZTF20abtxwfx/AT2020sev, a fast optical transient and candidate afterglow
  16. IPN triangulation of GRB 200826B
  17. GRB200826A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 620108997)
  18. IPN triangulation of GRB 200815A (short)
  19. GRB 200819A: Kitab, TSHAO optical upper limit
  20. Fermi GRB 200817A: Global MASTER-Net observations report
  21. GRB 200817A: Fermi GBM Final Real-time Localization
  22. Fermi trigger No 619270776: Global MASTER-Net observations report
  23. Fermi GRB 200803A: Global MASTER-Net observations report
  24. Fermi GRB 200802A: Global MASTER-Net observations report
  25. GRB 200802A: Fermi GBM Final Real-time Localization
  26. Fermi GRB 200801A: Global MASTER-Net observations report
  27. Swift Detection of an SGR-like flare from AX J1846.4-0258
  28. Swift GRB200801.84: Global MASTER-Net observations report
  29. Fermi GRB 200716A: Global MASTER-Net observations report
  30. GRB 200716C: Swift detection of a burst with an optical counterpart
  31. Fermi GRB 200714D: Global MASTER-Net observations report
  32. Fermi GRB 200714A: Global MASTER-Net observations report
  33. Fermi trigger No 616370565: Global MASTER-Net observations report
  34. Update of alert from the HAWC Burst Monitor HAWC-200709A
  35. Fermi GRB 200705A: Global MASTER-Net observations report
  36. Trigger 980513: Swift detection of SGR Swift J1818.0-1607
  37. GRB 200630A: Swift detection of a burst
  38. Fermi GRB 200626A: Global MASTER-Net observations report
  39. IceCube-200620A: One Candidate Counterpart from the Zwicky Transient Facility
  40. LIGO/Virgo MS200618aq: Retraction of a test binary neutron star candidate
  41. Fermi trigger No 614103490: Global MASTER-Net observations report
  42. Baksan Neutrino Observatory Alert 200617.47: Global MASTER-Net observations report
  43. GRB 200616B: Fermi GBM Final Real-time Localization
  44. GRB 200615B: MAXI/GSC detection
  45. Baksan Neutrino Observatory Alert 200614.34: Global MASTER-Net observations report
  46. GRB 200614A: Fermi GBM Final Real-time Localization
  47. Swift GRB200612.19: Global MASTER-Net OT detection
  48. Swift GRB200612.19: Global MASTER-Net observations report
  49. Fermi GRB 200604A: Global MASTER-Net observations report
  50. Baksan Neutrino Observatory Alert 200603.12: Global MASTER-Net observations report
  51. GRB 200529A: MITSuME Akeno optical upper limits
  52. Fermi GRB 200601A: Global MASTER-Net observations report
  53. IceCube-200530A: Candidate Counterparts from the Zwicky Transient Facility
  54. Swift GRB 200528A: Global MASTER-Net observations report
  55. GRB 200524A: CrAO optical observations
  56. GRB 171205A: ATCA observations of late-time radio emission
  57. Fermi GRB 200522B: Global MASTER-Net observations report
  58. GRB 200522B: Fermi GBM Final Real-time Localization
  59. Fermi trigger No 611676654: Global MASTER-Net observations report
  60. GRB 200519A: Swift detection of a burst with an optical afterglow
  61. Fermi trigger No 611434353: Global MASTER-Net observations report
  62. GRB 200517A: MAXI/GSC detection
  63. GRB 200514B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 611140062) - More Candidates
  64. GRB 200514A: MITSuME Akeno optical upper limits
  65. GRB200514B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 611140062)
  66. IceCube-200512A: No Candidate Counterparts from the Zwicky Transient Facility
  67. Konus-Wind observation of SGR 1935+2154 activity on 2020 May 10
  68. GRB 200509A: Swift detection of a burst with a possible optical counterpart
  69. Insight-HXMT X-ray and hard X-ray upper limits to the radio burst detected by FAST from SGR 1935+2154
  70. Fermi GBM trigger 200429866/609886052 is not a GRB
  71. Konus-Wind observation of hard X-ray counterpart of the radio burst from SGR 1935+2154
  72. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  73. IceCube-200425A: No significant detection in HAWC
  74. GRB 200423A: Fermi GBM Final Real-time Localization
  75. Fermi GRB 200421A: Global MASTER-Net observations report
  76. GRB 200421A: Fermi GBM Final Real-time Localization
  77. Fermi trigger No 608935505: Global MASTER-Net observations report
  78. GRB 200415A: MASTER imspection and possible localisation
  79. GRB 200416A: Swift detection of a burst with an optical afterglow
  80. Konus-Wind observation of GRB 200412A
  81. Baksan Neutrino Observatory Alert 200408.26: Global MASTER-Net observations report
  82. Swift GRB 200409A: Global MASTER-Net observations report
  83. Fermi GRB 200407A: Global MASTER-Net observations report
  84. Baksan Neutrino Observatory Alert 200406.3: Global MASTER-Net observations report
  85. Fermi GRB 200405A: Global MASTER-Net observations report
  86. Fermi GRB 200403B: Global MASTER-Net observations report
  87. Fermi GRB 200403A: Global MASTER-Net observations report
  88. Fermi GRB 200402C: Global MASTER-Net observations report
  89. Fermi GRB 200401A: Global MASTER-Net observations report
  90. GRB 200325B: Mondy continued observations
  91. Fermi trigger No 606918292: Global MASTER-Net observations report
  92. GRB 200326A: Fermi GBM Final Real-time Localization
  93. Fermi trigger No 606681997: Global MASTER-Net observations report
  94. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
  95. Fermi trigger No 606263732: Global MASTER-Net observations report
  96. LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
  97. LIGO/Virgo S200316bj: Upper limits from Insight-HXMT/HE observations
  98. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
  99. LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations
  100. LIGO/Virgo S200316bj: no counterpart candidates in the Swift/BAT observations

Advanced

Download all Circulars as a .tar.gz archive:
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