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"

45423 results found.

  1. GRB 241219A: SVOM/GRM observation
  2. EP241223a: Global MASTER-Net observations report
  3. EP241223a: EP-WXT detection of a fast X-ray transient
  4. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  5. GRB241113A: 7DT Optical upper limits
  6. Fermi Gamma-ray Burst Monitor trigger 756678579 / 241223854 is not a GRB
  7. Fermi GRB 241223A: Global MASTER-Net observations report
  8. GRB 241223A: GOTO optical observations summary
  9. GRB 241105A: JWST photometric observations of the host galaxy
  10. GRB 241223A: Swift ToO observations
  11. EP241217a: e-MERLIN radio observations
  12. GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)
  13. GRB 241223A: Fermi GBM Final Real-time Localization
  14. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  15. The EP-WXT trigger 01709129287 is likely a flaring star
  16. Fermi trigger No 756447119: Global MASTER-Net observations report
  17. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  18. Fermi Gamma-ray Burst Monitor trigger 756447119/241221175 is not a GRB
  19. Fermi GRB 241221A: Global MASTER-Net observations report
  20. GRB 241221A: Fermi GBM Final Real-time Localization
  21. GRB 241217A/EP241217b: SOAR afterglow detection
  22. EP241217a: Liverpool Telescope optical upper limit
  23. EP241021a: VLA radio detection
  24. GRB 241218A: Mondy AZT-33IK optical upper limit
  25. EP241217a : Leavitt Observatory optical upper limit
  26. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  27. EP241217a: 1.6m Mephisto multi-band optical observations
  28. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  29. GRB 241218A: Swift/UVOT Upper Limits
  30. EP241217a: optical upper limit with the Liverpool Telescope
  31. GRB 241209B: EP-FXT afterglow detection
  32. Konus-Wind detection of GRB 241204A (short/hard)
  33. GRB 241218A: NOT optical upper limits
  34. GRB 241218A: Swift-BAT refined analysis
  35. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  36. EP 241217a: NIR detection with P200/WIRC
  37. EP 241217a: Possible J-band detection with WINTER
  38. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  39. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  40. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  41. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  42. GRB 241217A / EP241217b: NOT optical upper limits
  43. GRB 241218A: REM optical upper limit
  44. GRB 241217A/EP241217b: REM optical/NIR upper limits
  45. EP241217a: REM optical/NIR upper limits
  46. GRB 241217a: Liverpool Telescope optical follow-up
  47. EP241217a: Liverpool Telescope optical follow-up
  48. GRB 241218A: Swift-XRT refined Analysis
  49. EP241217a: NOT optical observations
  50. EP241217a: GROWTH-India Telescope optical observations
  51. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  52. EP241119a: 7DT Optical upper limits
  53. EP241217b: Global MASTER-Net observations report
  54. GRB 241209A: ATCA radio follow-up observations
  55. EP241217a: Xinglong optical follow-up observations
  56. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  57. GRB 241218A: LCOGT Optical Upper Limit
  58. GRB 241218A: Enhanced Swift-XRT position
  59. EP241217a: Global MASTER-Net observations report
  60. GRB 241217A: GMG Optical Upper Limit
  61. GRB 241218A: Swift detection of a burst
  62. GRB 241217A : SVOM/VT optical afterglow detection
  63. GRB 241217A: Swift-XRT afterglow detection
  64. GRB 241217A: LCO optical upper limit
  65. GRB 241217A: GRANDMA/TAROT optical upperlimits
  66. EP241217a: Swift-XRT Detection
  67. EP241217A: Non-detection from Fermi-GBM Observations
  68. GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
  69. EP241217a: Gemini-North spectroscopic redshift z = 4.59
  70. EP241217a: Kinder optical follow-up observations
  71. GRB 241214A: GRBAlpha detection
  72. GRB 241213A (EP241213a): GRBAlpha detection
  73. GRB 241209D: GRBAlpha detection
  74. EP241217A: LCO optical observations
  75. EP241217a: Gemini-North detection of the likely optical counterpart
  76. EP241217a: EP detection of an X-ray transient
  77. The EP-WXT trigger 01709129023 is likely a flaring star
  78. EP241107a: VLA Radio Observation
  79. GRB 241213A: Swift-BAT refined analysis
  80. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  81. Konus-Wind detection of GRB 241213A (EP 241213a)
  82. GRB 241215A: Mondy AZT-33IK optical observations
  83. GRB 241212A: Swift-XRT observations
  84. GRB 241214A: SVOM/GRM observation
  85. The EP-WXT trigger 01709128948 is likely a flaring star
  86. GRB 241215A: Nanshan/HMT optical upper limit
  87. GRB 241215A: Montarrenti Observatory optical upper limit
  88. GRB 241215A: GROWTH-India telescope optical upper limit
  89. GRB 241215A: A long GRB detected by INTEGRAL
  90. Integral GRB241215.58: Global MASTER-Net observations report
  91. The EP-WXT trigger 01709128921 is likely a flaring star
  92. GRB 241213B: Swift-XRT observations
  93. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  94. GRB 241209B: SVOM/VT optical continuous fading
  95. EP trigger ID 01709128824 is not a real source
  96. GRB 241213A: SVOM/VT optical candidate
  97. GRB 241213B: Tiled Swift observations
  98. GRB 241213A: Swift/UVOT Upper Limits
  99. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  100. GRB 241213A: Swift-XRT refined Analysis

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