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').

18146 results found.

  1. SVOM/GRM observation of a short burst from soft gamma repeater Kes 73
  2. GRB 241128A: Swift-BAT refined analysis
  3. GRB 241127A: Swift-BAT refined analysis
  4. GRB 241127A: PRIME near-infrared detection
  5. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  6. Swift-XRT observations of IceCube -241127A
  7. Swift GRB 241128A: Global MASTER-Net observations report
  8. GRB 241128A: Swift-XRT refined Analysis
  9. GRB 241128A: Enhanced Swift-XRT position
  10. GRB 241128A: 1.5m OSN optical afterglow detection
  11. GRB 241128A: Swift-XRT afterglow detection
  12. GRB 241128A: Swift detection of a burst
  13. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  14. GRB 241127A: Swift/UVOT Detection
  15. GRB 241127A: Swift-XRT refined Analysis
  16. GRB 241127A: SVOM/GRM observation
  17. GRB 241127A: Enhanced Swift-XRT position
  18. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  19. Swift GRB241127.91: Global MASTER-Net OT detection
  20. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  21. GRB 241127A: Swift detection of a burst with an optical counterpart
  22. Swift GRB241127.91: Global MASTER-Net observations report
  23. Swift GRB241127.91: Global MASTER-Net OT detection
  24. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  25. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  26. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  27. IPN triangulation of GRB 241114B
  28. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  29. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  30. Trigger_18947: Swift ToO observations (retracted)
  31. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  32. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  33. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  34. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  35. EP241125a: EP detection of an X-ray transient
  36. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  37. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  38. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  39. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  40. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  41. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  42. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  43. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  44. Konus-Wind detection of GRB 241117A
  45. IPN triangulation of GRB 241117A
  46. GRB 241025A: VIRT Optical Upper Limit
  47. GRB 241115A: CALET Gamma-Ray Burst Monitor detection
  48. GRB 241115a: PRIME near-infrared upper limits
  49. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  50. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  51. GRB 241115B: Fermi GBM Observation
  52. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  53. GRB 241115C: Fermi GBM Observation
  54. GRB 241115A: Swift-XRT afterglow detection
  55. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  56. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  57. EP241113a: Swift XRT weak detection
  58. GRB 241115A: Fermi GBM Observation
  59. GRB 241115A: LCOGT Optical Upper Limits
  60. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  61. Swift GRB 241115A: Global MASTER-Net observations report
  62. GRB 241115A: Swift detection of a burst
  63. GRB 241113A: Swift-BAT refined analysis
  64. GRB 241113A: PRIME near-infrared upper limits
  65. GRB 241113A: J-band observations with WINTER
  66. GRB 241113B: Swift-XRT observations
  67. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  68. GRB 241113A: KAIT optical observations
  69. GRB 241113A: Swift-XRT refined Analysis
  70. GRB 241113A: Swift/UVOT Detection
  71. GRB 241113A: REM detection of the optical/NIR afterglow
  72. Konus-Wind detection of GRB 241107A (short/hard)
  73. GRB 241113B: Swift ToO observations
  74. GRB 241113A: LCO optical observations
  75. GRB 241113A: Enhanced Swift-XRT position
  76. GRB241113A: LCOGT (40-cm) optical counterpart detection
  77. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  78. GRB 241113A: Swift detection of a burst with an optical counterpart
  79. Swift GRB241113.33: Global MASTER-Net observations report
  80. GRB 241107A: GROWTH-India telescope optical upper limit
  81. GRB 241112B: Swift-XRT afterglow detection
  82. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  83. GRB 241112B: Swift ToO observations
  84. GRB 241107A: INTEGRAL IBIS localization
  85. IPN triangulation of GRB 241107A (short/hard)
  86. GRB 241025A: VZLUSAT-2 detection
  87. GRB 241108A: Swift-XRT observations
  88. GRB 241108A: Swift ToO observations
  89. GRB 241030A: TESS observations
  90. GRB 241105A: EP-FXT follow-up observations
  91. GRB 241105A: SVOM/GRM observation
  92. GRB 241105a: PRIME near-infrared upper limits
  93. GRB 241105A: Swift/UVOT Detection
  94. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  95. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  96. GRB 241105A: BOOTES-7 optical detection
  97. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  98. GRB 241105A: Swift-XRT afterglow detection
  99. GRB 241104A: Swift-XRT observations
  100. GRB 241105A: Swift ToO observations

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