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"

20966 results found.

  1. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  2. EP241126a: WFST Observations
  3. IceCube Alert 241127.59: Global MASTER-Net observations report
  4. Swift GRB241127.91: Global MASTER-Net observations report
  5. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  6. LIGO/Virgo/KAGRA S241127aj: NED Galaxies in the Localization Volume
  7. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations (duplicate submission of 38345)
  8. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations (duplicate submission of 38345).
  9. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  10. EP241126a: Optical Upper limits with Kinder observations
  11. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  12. EP241126a: GSP detects optical counterpart
  13. EP241126a: TRT optical counterpart detection
  14. EP241126a: EP detection of a fast X-ray transient
  15. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  16. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  17. Trigger_18947: Swift ToO observations (retracted)
  18. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  19. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  20. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  21. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  22. LIGO/Virgo/KAGRA S241125n: HCT upper limit
  23. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  24. GRB 241026A: radio detection with the VLA
  25. EP241125a: Optical upper limit with Kinder observations
  26. EP241125a: EP detection of an X-ray transient
  27. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  28. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  29. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  30. GRB 241113B: SVOM/VT optical afterglow observations
  31. GRB 241105A: ATCA radio detection
  32. GRB241120A: OHP/T193 optical observations
  33. EP241021a and EP241026b: Keck/LRIS spectroscopic observations
  34. EP trigger ID 01709065118: Keck/LRIS spectroscopic observations
  35. EP-WXT trigger 01709018832: Lick/Kast spectroscopy with the 3 m Shane telescope
  36. GRB 241120A: Mondy and AbAO optical observations
  37. EP241119a: Optical upper limits with Kinder observations
  38. EP241119a: GIT optical upper limits
  39. GRB 241113A: Possible ATCA Radio detection
  40. EP241119a : J-band observations with WINTER
  41. Integral GRB241120.25: Global MASTER-Net observations report
  42. EP241119a: Global MASTER-Net observations report
  43. EP241119a: EP detection of a fast X-ray transient
  44. GRB 241112B: Mephisto further optical observations
  45. GRB 241030A: J-band observations
  46. GRB 241115a: PRIME near-infrared upper limits
  47. Fermi GRB 241118A: Global MASTER-Net observations report
  48. Fermi GRB 241117B: Global MASTER-Net observations report
  49. Fermi GRB 241117A: Global MASTER-Net observations report
  50. GRB 241115A: Swift-XRT afterglow detection
  51. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  52. Fermi GRB 241115B: Global MASTER-Net observations report
  53. EP241115a: Global MASTER-Net observations report
  54. EP241115a: EP detection of a fast X-ray transient
  55. EP241113a: No Detection in Fermi-GBM Observations
  56. Swift GRB 241115A: Global MASTER-Net observations report
  57. Fermi GRB 241115A: Global MASTER-Net observations report
  58. EP 241113a: LBT possible optical counterpart
  59. GRB 241113B: KAIT Optical Afterglow Candidate
  60. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  61. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  62. GRB 241113A: PRIME near-infrared upper limits
  63. Fermi GRB 241114A: Global MASTER-Net observations report
  64. EP241113a: Global MASTER-Net observations report
  65. GRB 241113B: J-band upper limit from WINTER
  66. GRB 241113A: J-band observations with WINTER
  67. EP241113a : J-band observations with WINTER
  68. GRB 241030A: LCO optical observation
  69. GRB 241113B: Swift-XRT observations
  70. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  71. GRB 241113A: KAIT optical observations
  72. EP241113b: Global MASTER-Net observations report
  73. Fermi-LAT gamma-ray observations of IceCube-241113A
  74. EP241113a: EP on-board trigger and autonomous follow-up observation
  75. EP241107a: SOAR upper limits
  76. GRB 241113A: Swift/UVOT Detection
  77. GRB 241113A: REM detection of the optical/NIR afterglow
  78. GRB 241113B: Swift ToO observations
  79. GRB 241113A: LCO optical observations
  80. GRB241113A: LCOGT (40-cm) optical counterpart detection
  81. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  82. Swift GRB241113.33: Global MASTER-Net observations report
  83. Fermi trigger No 753166198: Global MASTER-Net observations report
  84. GRB 241105A: ATCA Radio Upper Limits
  85. GRB 241112B: AbAO optical upper limit
  86. GRB 241107A: GROWTH-India telescope optical upper limit
  87. IceCube Alert 241113.02: Global MASTER-Net observations report
  88. Fermi GRB 241112A: Global MASTER-Net observations report
  89. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  90. GRB 241112B: Swift-XRT afterglow detection
  91. GRB 241112B: SVOM/VT afterglow detection
  92. GRB 241112B: Mephisto optical upper limits
  93. GRB 241112B: GOTO optical upper limits
  94. GRB 241112B: Swift ToO observations
  95. EP241107a: EP-FXT follow-up observations
  96. LIGO/Virgo/KAGRA S241110br: NED Galaxies in the Localization Volume
  97. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  98. Fermi trigger No 752990530: Global MASTER-Net observations report
  99. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  100. Fermi trigger No 752878030: Global MASTER-Net observations report

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