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"

5515 results found.

  1. EP250109a: GOTO optical upper limits
  2. GRB 250103A: 1.6m Mephisto optical observations
  3. GRB 250103A: Swift-XRT afterglow detection
  4. Fermi GRB 250107B: Global MASTER-Net observations report
  5. Fermi trigger No 757753930: Global MASTER-Net observations report
  6. GRB 250103B: Swift-XRT refined Analysis
  7. GRB 250103B: VLT/X-shooter spectroscopic redshift z = 1.416
  8. GRB 250103A: Swift-XRT observations
  9. GRB 250103B：SVOM/VT optical counterpart
  10. GRB 250103A: Montarrenti Observatory optical detection
  11. GRB 250101A: further LCOGT optical afterglow observations
  12. GRB 250103A: Redshift 4.01 from OSIRIS+/GTC
  13. GRB 250103A: TSHAO optical upper limit
  14. GRB 250103A: Fermi GBM Observation
  15. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  16. Swift GRB 250103B: Global MASTER-Net observations report
  17. GRB 250101a: Liverpool Telescope optical follow-up
  18. GRB 250103B: SVOM detection of a long burst
  19. GRB 250103A: Xinglong 2.16m Optical Candidate
  20. Fermi GRB 250102A: Global MASTER-Net observations report
  21. GRB 250103A: GOTO optical upper limit
  22. IceCube Alert 250102.58: Global MASTER-Net observations report
  23. GRB 250101A: LCO optical counterpart detection
  24. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  25. Konus-Wind detection of GRB 241228A
  26. GRB 241229A: GOTO optical upper limits
  27. Fermi GRB 241228B: Global MASTER-Net observations report
  28. GRB 241228A: Fermi GBM Observation
  29. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  30. GRB 241228A: Swift detection of a burst
  31. Fermi trigger No 756678579: Global MASTER-Net observations report
  32. EP241223a: Global MASTER-Net observations report
  33. Konus-Wind detection of GRB 241204A (short/hard)
  34. GRB 241217A/EP241217b: REM optical/NIR upper limits
  35. GRB 241218a: Liverpool Telescope optical follow-up
  36. EP241217a: Liverpool Telescope optical follow-up
  37. GRB 241218A: LCOGT Optical Upper Limit
  38. EP241217a: Global MASTER-Net observations report
  39. EP241217A: Non-detection from Fermi-GBM Observations
  40. GRB 241214A: GRBAlpha detection
  41. EP241217a: Gemini-North detection of the likely optical counterpart
  42. EP241217a: EP detection of an X-ray transient
  43. GRB 241213B: MAXI/GSC detection
  44. GRB 241213A: REM optical/NIR upper limits
  45. GRB 241212A : SVOM/VT bright optical afterglow
  46. Konus-Wind detection of GRB 241209B
  47. GRB 241209B: GRBAlpha detection
  48. GRB 241206C: GRBAlpha detection
  49. Fermi Gamma-ray Burst Monitor trigger 755485387 / 241210044 is not a GRB
  50. EP241208a: Global MASTER-Net observations report
  51. Fermi trigger No 755485387: Global MASTER-Net observations report
  52. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  53. Fermi GRB 241209C: Global MASTER-Net observations report
  54. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  55. Fermi GRB 241209A: Global MASTER-Net observations report
  56. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  57. Fermi GRB 241207B: Global MASTER-Net observations report
  58. Fermi GRB 241207A: Global MASTER-Net observations report
  59. GRB 241206C: SVOM/GRM observation of a likely short burst
  60. GRB 241204A: DDOTI Upper Limits on the Afterglow
  61. GRB 241204A: Fermi GBM Observation
  62. Fermi GRB 241204A: Global MASTER-Net observations report
  63. GRB 241204A: Fermi-LAT detection
  64. EP241202b: Kinder optical counterpart candidate
  65. EP241202b: Global MASTER-Net observations report
  66. EP241201a: Kinder optical counterpart candidate
  67. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  68. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  69. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  70. EP241126a: GSP detects optical counterpart
  71. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  72. Konus-Wind detection of GRB 241117A
  73. IPN triangulation of GRB 241117A
  74. GRB 241114B: Insight-HXMT/HE detection
  75. Fermi GRB 241118A: Global MASTER-Net observations report
  76. GRB 241117A: Fermi GBM Detection
  77. Fermi GRB 241117A: Global MASTER-Net observations report
  78. GRB 241117A: Fermi GBM Final Real-time Localization
  79. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  80. EP241113a: Swift XRT weak detection
  81. GRB 241113A: J-band observations with WINTER
  82. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  83. GRB 241113A: KAIT optical observations
  84. EP241113b: Global MASTER-Net observations report
  85. GRB 241113A: REM detection of the optical/NIR afterglow
  86. Fermi trigger No 753166198: Global MASTER-Net observations report
  87. GRB 241112B: AbAO optical upper limit
  88. IPN triangulation of GRB 241107A (short/hard)
  89. Fermi trigger No 752878030: Global MASTER-Net observations report
  90. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  91. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  92. EP241107a: AKO Optical Afterglow Follow-Up Observations
  93. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  94. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  95. EP241107a: AKO Optical Afterglow Detection
  96. EP241101a: CrAO ZTSH optical observations
  97. GRB 241030A: Mondy optical observations
  98. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  99. GRB 240511A: LCO upper limits
  100. Fermi GRB 241105A: 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