Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. 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"

21962 results found.

  1. LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume
  2. LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
  3. GRB 241229A: EP-FXT X-ray afterglow confirmation
  4. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  5. EP241217A: J band upper limit by SYSU 80cm telescope
  6. GRB 241228B: SAO RAS optical observations
  7. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  8. GRB 241229A: SAO RAS optical observations
  9. GRB 241229B: SVOM/VT optical candidate
  10. GRB 241229A: Swift-XRT observations
  11. EP240702a: 7DT Optical upper limits
  12. GRB 240606B: 7DT Optical upper limits
  13. Fermi trigger No 757231333: Global MASTER-Net observations report
  14. GRB241229B: UVOT upper limits
  15. GRB 241228B: D50 optical detection
  16. GRB 241228B: Fermi GBM Observation
  17. GRB 241228B: Swift-XRT afterglow detection
  18. GRB 241229A: Swift ToO observations
  19. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  20. GRB 241228A: Mondy optical afterglow observations
  21. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  22. Swift GRB 241229B: Global MASTER-Net observations report
  23. GRB 241229A: GOTO optical upper limits
  24. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  25. GRB 241228A: NOT optical upper limits
  26. GRB 241228B: LCO optical observation
  27. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  28. Fermi GRB 241228B: Global MASTER-Net observations report
  29. GRB241228B: GROWTH-India Telescope optical observations
  30. Swift GRB 241228A: Global MASTER-Net observations report
  31. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  32. GRB 241228B: GOTO24jmz optical follow-up observations
  33. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  34. GRB 241228B: Swift ToO observations
  35. GRB 241228B: TRT optical counterpart confirmation
  36. GRB 241228A: Swift/UVOT Upper Limits
  37. GRB 241228B: GOTO possible optical counterpart candidate
  38. GRB 241217A/EP241217b: continued SOAR observations
  39. Fermi GRB 241226A: Global MASTER-Net observations report
  40. EP241223a: Mondy AZT-33IK optical observations
  41. GRB 241029A: LCO optical observation
  42. GRB 241223A: Swift-XRT observations
  43. GRB 241029A: AbAO AS-32 optical observations
  44. Fermi trigger No 756678579: Global MASTER-Net observations report
  45. IceCube Alert 241224.30: Global MASTER-Net observations report
  46. EP241223a: Global MASTER-Net observations report
  47. EP241223a: EP-WXT detection of a fast X-ray transient
  48. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  49. GRB241113A: 7DT Optical upper limits
  50. Fermi GRB 241223A: Global MASTER-Net observations report
  51. GRB 241223A: GOTO optical observations summary
  52. GRB 241105A: JWST photometric observations of the host galaxy
  53. GRB 241223A: Swift ToO observations
  54. EP241217a: e-MERLIN radio observations
  55. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  56. Fermi trigger No 756447119: Global MASTER-Net observations report
  57. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  58. Fermi GRB 241221A: Global MASTER-Net observations report
  59. EP241021a: VLA radio detection
  60. GRB 241218A: Mondy AZT-33IK optical upper limit
  61. EP241217a : Leavitt Observatory optical upper limit
  62. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  63. EP241217a: 1.6m Mephisto multi-band optical observations
  64. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  65. GRB 241218A: Swift/UVOT Upper Limits
  66. GRB 241218A: NOT optical upper limits
  67. EP 241217a: NIR detection with P200/WIRC
  68. EP 241217a: Possible J-band detection with WINTER
  69. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  70. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  71. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  72. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  73. GRB 241217A / EP241217b: NOT optical upper limits
  74. GRB 241218A: REM optical upper limit
  75. GRB 241217A/EP241217b: REM optical/NIR upper limits
  76. EP241217a: REM optical/NIR upper limits
  77. EP241217a: Liverpool Telescope optical follow-up
  78. EP241217a: NOT optical observations
  79. EP241217a: GROWTH-India Telescope optical observations
  80. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  81. EP241119a: 7DT Optical upper limits
  82. EP241217b: Global MASTER-Net observations report
  83. GRB 241209A: ATCA radio follow-up observations
  84. EP241217a: Xinglong optical follow-up observations
  85. EP241217a: Global MASTER-Net observations report
  86. GRB 241217A : SVOM/VT optical afterglow detection
  87. GRB 241217A: Swift-XRT afterglow detection
  88. GRB 241217A: GRANDMA/TAROT optical upperlimits
  89. EP241217a: Swift-XRT Detection
  90. EP241217A: Non-detection from Fermi-GBM Observations
  91. EP241217a: Gemini-North spectroscopic redshift z = 4.59
  92. EP241217a: Kinder optical follow-up observations
  93. EP241217A: LCO optical observations
  94. EP241217a: Gemini-North detection of the likely optical counterpart
  95. EP241217a: EP detection of an X-ray transient
  96. EP241107a: VLA Radio Observation
  97. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  98. GRB 241215A: Mondy AZT-33IK optical observations
  99. GRB 241212A: Swift-XRT observations
  100. GRB 241215A: Nanshan/HMT optical upper limit

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