Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

43124 results found.

  1. EP240702a: 7DT Optical upper limits
  2. GRB 240606B: 7DT Optical upper limits
  3. Fermi trigger No 757231333: Global MASTER-Net observations report
  4. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  5. GRB 241229B: Swift-BAT refined analysis
  6. LIGO/Virgo/KAGRA S241225v: Updated Sky localization
  7. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  8. GRB241229B: UVOT upper limits
  9. GRB 241229C: Fermi GBM Final Real-time Localization
  10. GRB 241228B: D50 optical detection
  11. GRB 241228B: Fermi GBM Observation
  12. GRB 241228B: Swift-XRT afterglow detection
  13. GRB 241229B: Fermi GBM Observation
  14. GRB 241229A: Swift ToO observations
  15. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  16. GRB 241228A: Mondy optical afterglow observations
  17. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  18. Swift GRB 241229B: Global MASTER-Net observations report
  19. GRB 241229A: GOTO optical upper limits
  20. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  21. GRB 241228A: NOT optical upper limits
  22. GRB 241228B: LCO optical observation
  23. GRB 241228A: Swift-BAT refined analysis
  24. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  25. GRB 241229B: Swift detection of a burst
  26. GRB 241229B: Fermi GBM Final Real-time Localization
  27. GRB 241229A: SVOM detection of a long burst
  28. Fermi GRB 241228B: Global MASTER-Net observations report
  29. GRB 241228A: Fermi GBM Observation
  30. GRB241228B: GROWTH-India Telescope optical observations
  31. Swift GRB 241228A: Global MASTER-Net observations report
  32. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  33. GRB 241228B: GOTO24jmz optical follow-up observations
  34. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  35. GRB 241228A: GROWTH-India telescope optical upper limit
  36. GRB 241228B: Swift ToO observations
  37. GRB 241228B: TRT optical counterpart confirmation
  38. GRB 241228A: Swift-XRT refined Analysis
  39. GRB 241228A: Swift/UVOT Upper Limits
  40. GRB 241228B: GOTO possible optical counterpart candidate
  41. GRB 241228A: Enhanced Swift-XRT position
  42. GRB 241228B: Fermi GBM Final Real-time Localization
  43. GRB 241228A: Swift detection of a burst
  44. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  45. LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches
  46. GRB 241223A: GRBAlpha detection
  47. GRB 241212A: VZLUSAT-2 detection
  48. GRB 241217A/EP241217b: continued SOAR observations
  49. Fermi GRB 241226A: Global MASTER-Net observations report
  50. GRB 241226A: Fermi GBM Final Real-time Localization
  51. EP241223a: Mondy AZT-33IK optical observations
  52. GRB 241029A: LCO optical observation
  53. GRB 241223A: Swift-XRT observations
  54. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  55. GRB 241029A: AbAO AS-32 optical observations
  56. GRB 241223A: Fermi GBM Detection
  57. Fermi trigger No 756678579: Global MASTER-Net observations report
  58. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  59. IceCube-241224A - IceCube observation of a high-energy neutrino candidate track-like event
  60. IceCube Alert 241224.30: Global MASTER-Net observations report
  61. GRB 241219A: SVOM/GRM observation
  62. EP241223a: Global MASTER-Net observations report
  63. EP241223a: EP-WXT detection of a fast X-ray transient
  64. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  65. GRB241113A: 7DT Optical upper limits
  66. Fermi Gamma-ray Burst Monitor trigger 756678579 / 241223854 is not a GRB
  67. Fermi GRB 241223A: Global MASTER-Net observations report
  68. GRB 241223A: GOTO optical observations summary
  69. GRB 241105A: JWST photometric observations of the host galaxy
  70. GRB 241223A: Swift ToO observations
  71. EP241217a: e-MERLIN radio observations
  72. GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)
  73. GRB 241223A: Fermi GBM Final Real-time Localization
  74. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  75. The EP-WXT trigger 01709129287 is likely a flaring star
  76. Fermi trigger No 756447119: Global MASTER-Net observations report
  77. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  78. Fermi GRB 241221A: Global MASTER-Net observations report
  79. GRB 241221A: Fermi GBM Final Real-time Localization
  80. GRB 241217A/EP241217b: SOAR afterglow detection
  81. EP241217a: Liverpool Telescope optical upper limit
  82. EP241021a: VLA radio detection
  83. GRB 241218A: Mondy AZT-33IK optical upper limit
  84. EP241217a : Leavitt Observatory optical upper limit
  85. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  86. EP241217a: 1.6m Mephisto multi-band optical observations
  87. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  88. GRB 241218A: Swift/UVOT Upper Limits
  89. EP241217a: optical upper limit with the Liverpool Telescope
  90. GRB 241209B: EP-FXT afterglow detection
  91. Konus-Wind detection of GRB 241204A (short/hard)
  92. GRB 241218A: NOT optical upper limits
  93. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  94. EP 241217a: NIR detection with P200/WIRC
  95. EP 241217a: Possible J-band detection with WINTER
  96. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  97. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  98. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  99. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  100. GRB 241217A / EP241217b: NOT optical upper limits

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