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 241212A: Swift-XRT observations
  2. GRB 241215A: Nanshan/HMT optical upper limit
  3. GRB 241215A: Montarrenti Observatory optical upper limit
  4. Integral GRB241215.58: Global MASTER-Net observations report
  5. GRB 241213B: Swift-XRT observations
  6. GRB 241213A: SVOM/VT optical candidate
  7. GRB 241213B: Tiled Swift observations
  8. GRB 241213A: Swift/UVOT Upper Limits
  9. EP241208a: NOT optical upper limits
  10. GRB 241212A: Swift ToO observations
  11. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
  12. GRB 241213A: REM optical/NIR upper limits
  13. GRB241212A: OHP/T193 optical observations
  14. GRB 241213A: SAO RAS optical upper limit
  15. Swift GRB 241213A: Global MASTER-Net observations report
  16. GRB 241212A : SVOM/VT bright optical afterglow
  17. GRB 241209B: GRANDMA/TRT upper limit
  18. GRB 241207A: TSHAO Zeiss-1000 optical observations
  19. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  20. GRB 241209A: Chandra X-ray Detection
  21. GRB 241209D: REM optical/NIR upper limits
  22. GRB 241209B: Swift-XRT afterglow detection
  23. EP241208a: Optical upper limit with Kinder observations
  24. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  25. GRB 241209A: EP-FXT follow-up observations
  26. GRB 241209B: SVOM/VT afterglow detection
  27. EP241208a: Global MASTER-Net observations report
  28. EP241208a: EP-FXT follow-up observations
  29. Fermi trigger No 755485387: Global MASTER-Net observations report
  30. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  31. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  32. GRB 241209D: COLIBRÍ detection of the afterglow
  33. GRB 241209A: COLIBRÍ Optical Upper Limit
  34. Fermi GRB 241209D: Global MASTER-Net observations report
  35. GRB 241209A: Fermi GBM Observation
  36. GRB 241209A: GRANDMA/TAROT upper limit
  37. Swift GRB 241209D: Global MASTER-Net observations report
  38. Fermi GRB 241209C: Global MASTER-Net observations report
  39. Fermi GRB 241209E: Global MASTER-Net observations report
  40. GRB 241209B: Swift ToO observations
  41. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  42. GRB 241209A: REM optical/NIR observations
  43. GRB 241209A: VLT/X-shooter spectroscopy
  44. GRB 241209A: VLT optical observations
  45. Fermi GRB 241209A: Global MASTER-Net observations report
  46. GRB 241209A: GOTO optical upper limits
  47. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  48. EP241208a: EP detection of a fast X-ray transient
  49. Swift GRB241209.23: Global MASTER-Net observations report
  50. Fermi GRB 241207B: Global MASTER-Net observations report
  51. GRB 241206A: DDOTI Upper Limit on the Afterglow
  52. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  53. EP241206a: BOOTES Global Network optical limits
  54. GRB 241207C: MASTER optical observations
  55. Fermi trigger No 755225799: Global MASTER-Net observations report
  56. GRB 241207C: Tiled Swift observations
  57. Fermi trigger No 755277791: Global MASTER-Net observations report
  58. Fermi GRB 241207A: Global MASTER-Net observations report
  59. EP241206a: Global MASTER-Net observations report
  60. EP241206a: EP detection of a fast X-ray transient
  61. GRB 241206B: SVOM/MXT observations: a probable flare from the QSO 1ES 1959+650
  62. EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
  63. Fermi GRB 241206A: Global MASTER-Net observations report
  64. GRB 241204A: COLIBRÍ Optical Upper Limit
  65. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  66. GRB 241204A: DDOTI Upper Limits on the Afterglow
  67. Fermi GRB 241204A: Global MASTER-Net observations report
  68. GRB 241128A : RAPAS follow-up observations
  69. EP241202b: Upper limits from Fermi-GBM Observations
  70. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  71. EP241202b: Kinder optical counterpart candidate
  72. EP241201a: EP-FXT follow-up observations
  73. EP241202b: Global MASTER-Net observations report
  74. EP241202b: EP detection of a fast X-ray transient
  75. EP241201a: NOT optical observations
  76. GRB 241128A: Swift/UVOT Upper Limits
  77. EP241201a: Kinder optical counterpart candidate
  78. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  79. EP241201a: Global MASTER-Net observations report
  80. EP241201a: EP detection of a fast X-ray transient
  81. EP241126a: SOAR observations of the optical counterpart
  82. Fermi GRB 241201A: Global MASTER-Net observations report
  83. EP241126a: 1.6m Mephisto Optical Upper Limits
  84. Fermi trigger No 754701230: Global MASTER-Net observations report
  85. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  86. EP241126a: NOT optical observations
  87. GRB 241127A: PRIME near-infrared detection
  88. GRB 241128A: Mondy optical observations
  89. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  90. Swift-XRT observations of IceCube -241127A
  91. Swift GRB 241128A: Global MASTER-Net observations report
  92. Fermi-LAT gamma-ray observations of IceCube-241127A
  93. EP241126a: SVOM/VT observations
  94. GRB 241128A: NOT optical observations
  95. GRB 241128A: LCO optical detection
  96. GRB 241128A: 1.5m OSN optical afterglow detection
  97. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  98. Fermi trigger No 754492985: Global MASTER-Net observations report
  99. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  100. GRB 241127A: Swift/UVOT Detection

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