Skip to main content
End of INTEGRAL Operations. 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').

18188 results found.

  1. EP241213a: EP detection of An X-ray Transient
  2. GRB 241213A: REM optical/NIR upper limits
  3. GRB 241213A: Enhanced Swift-XRT position
  4. Swift GRB 241213A: Global MASTER-Net observations report
  5. GRB 241213A: Swift detection of a burst
  6. GRB 241209A: Chandra X-ray Detection
  7. Konus-Wind detection of GRB 241209B
  8. GRB 241209B: GRBAlpha detection
  9. GRB 241129A: Fermi GBM Observation
  10. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  11. GRB 241209D: REM optical/NIR upper limits
  12. Konus-Wind detection of GRB 241209D
  13. GRB 241209B: Swift-XRT afterglow detection
  14. GRB 241209C: Fermi GBM Observation
  15. GRB 241209A: Swift-XRT refined Analysis
  16. GRB 241209D: AstroSat CZTI detection
  17. GRB 241209A: EP-FXT follow-up observations
  18. GRB 241209B: SVOM/VT afterglow detection
  19. GRB 241207B: Fermi GBM Observation
  20. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  21. GRB 241209D: Swift-XRT refined Analysis
  22. GRB 241209D: Fermi GBM Observation
  23. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  24. GRB 241209D: COLIBRÍ detection of the afterglow
  25. GRB 241209A: COLIBRÍ Optical Upper Limit
  26. GRB 241209A: Fermi GBM Observation
  27. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  28. GRB 241209A: GRANDMA/TAROT upper limit
  29. Swift GRB 241209D: Global MASTER-Net observations report
  30. GRB 241209B: Swift ToO observations
  31. GRB 241209A: REM optical/NIR observations
  32. GRB 241209D: Enhanced Swift-XRT position
  33. GRB 241209D: Swift detection of a burst
  34. GRB 241209A: Enhanced Swift-XRT position
  35. GRB 241209A: GOTO optical upper limits
  36. GRB 241209A: Prompt enhanced Swift-XRT position
  37. GRB 241209A: Swift detection of a short burst
  38. Swift GRB241209.23: Global MASTER-Net observations report
  39. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  40. GRB 241206A: DDOTI Upper Limit on the Afterglow
  41. GRB 241207C: Tiled Swift observations
  42. GRB 241206A: Fermi GBM observation
  43. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  44. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  45. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  46. GRB 241128A: Swift/UVOT Upper Limits
  47. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  48. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  49. SVOM/GRM observation of a short burst from soft gamma repeater Kes 73
  50. GRB 241128A: Swift-BAT refined analysis
  51. GRB 241127A: Swift-BAT refined analysis
  52. GRB 241127A: PRIME near-infrared detection
  53. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  54. Swift-XRT observations of IceCube -241127A
  55. Swift GRB 241128A: Global MASTER-Net observations report
  56. GRB 241128A: Swift-XRT refined Analysis
  57. GRB 241128A: Enhanced Swift-XRT position
  58. GRB 241128A: 1.5m OSN optical afterglow detection
  59. GRB 241128A: Swift-XRT afterglow detection
  60. GRB 241128A: Swift detection of a burst
  61. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  62. GRB 241127A: Swift/UVOT Detection
  63. GRB 241127A: Swift-XRT refined Analysis
  64. GRB 241127A: SVOM/GRM observation
  65. GRB 241127A: Enhanced Swift-XRT position
  66. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  67. Swift GRB241127.91: Global MASTER-Net OT detection
  68. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  69. GRB 241127A: Swift detection of a burst with an optical counterpart
  70. Swift GRB241127.91: Global MASTER-Net observations report
  71. Swift GRB241127.91: Global MASTER-Net OT detection
  72. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  73. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  74. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  75. IPN triangulation of GRB 241114B
  76. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  77. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  78. Trigger_18947: Swift ToO observations (retracted)
  79. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  80. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  81. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  82. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  83. EP241125a: EP detection of an X-ray transient
  84. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  85. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  86. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  87. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  88. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  89. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  90. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  91. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  92. Konus-Wind detection of GRB 241117A
  93. IPN triangulation of GRB 241117A
  94. GRB 241025A: VIRT Optical Upper Limit
  95. GRB 241115A: CALET Gamma-Ray Burst Monitor detection
  96. GRB 241115a: PRIME near-infrared upper limits
  97. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  98. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  99. GRB 241115B: Fermi GBM Observation
  100. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst

Advanced

Download all Circulars as a .tar.gz archive:
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