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"

43118 results found.

  1. GRB 250126A: BALROG localization (Fermi Trigger 759560335 / GRB 250126208)
  2. GRB 250126A: Fermi GBM Final Real-time Localization
  3. GECAM-A detection of a bright burst from SGR 1E1841-045
  4. GRB 250118A: Fermi GBM Observation
  5. EP250125a: Optical upper limit with Kinder observations
  6. EP250125a: REM optical counterpart detection
  7. GRB 250119C: Fermi GBM Observation
  8. EP250125a: Swift/XRT detection of a fading counterpart
  9. EP250125a: a new X-ray transient detected by Einstein Probe
  10. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  11. The EP-WXT trigger 01709130758 is a false trigger
  12. The EP-WXT trigger 01709130758 is a false trigger
  13. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  14. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  15. IPN triangulation of a bright burst from SGR 1E1841-045
  16. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  17. EP250108a: AbAO, CMO and Terskol optical upper limits
  18. Konus-Wind detection of GRB 250118B
  19. GRB 250121A: Fermi GBM Observation
  20. IPN triangulation of GRB 250118B
  21. Konus-Wind detection of GRB 250119B
  22. IPN triangulation of GRB 250119B
  23. GRB 250122A: Fermi GBM Final Real-time Localization
  24. Improved IPN triangulation of GRB 250107C
  25. GRB 250114A: Swift-BAT refined analysis
  26. GRB 250121A: INTEGRAL/SPI-ACS detection
  27. GRB 250121A: Fermi-LAT detection
  28. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  29. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  30. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  31. GRB 250121A: Fermi GBM Final Real-time Localization
  32. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  33. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  34. GRB 250119B: Fermi GBM Observation
  35. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  36. Konus-Wind detection of GRB 250117A
  37. IPN triangulation of GRB 250117A (short)
  38. ATCA detection of possible radio counterpart to GRB 250114A
  39. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  40. GRB 250119B: INTEGRAL/SPI-ACS detection
  41. LIGO/Virgo/KAGRA S250119cv: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  42. EP 250108A: Late-time optical observation by LCO
  43. GRB 250117A: SVOM/GRM observation of a short burst
  44. LIGO/Virgo/KAGRA S250105bn: 1 counterpart neutrino candidate event from an IceCube neutrino search
  45. LIGO/Virgo/KAGRA S250119cv: Updated NED Galaxies in the Localization Volume
  46. LIGO/Virgo/KAGRA S250119cv: Updated Sky localization and EM Bright Classification
  47. GRB 250119C: Fermi GBM Final Real-time Localization
  48. LIGO/Virgo/KAGRA S250119cv: NED Galaxies in the Localization Volume
  49. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  50. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  51. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  52. LIGO/Virgo/KAGRA S250119ag: Updated Sky localization
  53. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  54. EP250108a / AT 2025kg: the kangaroo is hopping, evidence for optical rebrightening
  55. GRB 250117A: GECAM observation of a short burst
  56. LIGO/Virgo/KAGRA S250118dp: Updated Sky localization
  57. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  58. GRB 250119B: Fermi GBM Final Real-time Localization
  59. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  60. GRB 250119A: Fermi GBM Final Real-time Localization
  61. GRB 250118A: Fermi GBM Final Real-time Localization
  62. LIGO/Virgo/KAGRA S250118dp: Identification of a GW compact binary merger candidate
  63. LIGO/Virgo/KAGRA S250118t: Updated Sky localization
  64. LIGO/Virgo/KAGRA S250118az: Identification of a GW compact binary merger candidate
  65. EP250108a / AT2025kg: GMG Optical Observations
  66. LIGO/Virgo/KAGRA S250118t: Identification of a GW compact binary merger candidate
  67. EP250108a / AT2025kg: VLA radio upper limit
  68. Konus-Wind detection of GRB 250116A
  69. GRB 250116A: GECAM-B detection of a long burst
  70. GRB 241217A / EP241217B: radio detection with the VLA
  71. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  72. Swift Trigger 1282245 is not a GRB
  73. GRB 250116A: Fermi-LAT detection
  74. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  75. GRB 250114B: Swift-XRT afterglow detection
  76. GRB 250114B: SVOM/VT upper limit
  77. EP250108a: MeerKAT radio upper limit
  78. LIGO/Virgo/KAGRA S250114ax: Updated NED Galaxies in the Localization Volume
  79. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  80. LIGO/Virgo/KAGRA S250114ax: Updated Sky localization
  81. Konus-Wind detection of GRB 250113A
  82. IPN triangulation of GRB 250113A
  83. GRB 250114B: Liverpool Telescope optical upper limit
  84. LIGO/Virgo/KAGRA S250114ax: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  85. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  86. GRB 250114B: Swift-XRT observations
  87. GRB 250114A: LCO optical counterpart detection.
  88. GRB 250114B: OHP/T193 optical upper limit
  89. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  90. GRB 250114A: Swift-XRT refined Analysis
  91. Integral GRB250114.55: Global MASTER-Net observations report
  92. GRB 250114A: LCOGT optical afterglow i-band detection
  93. GRB 250114B : GIT optical upper limit
  94. GRB 250114B: Swift ToO observations
  95. EP250111a: SAO RAS optical upper limit
  96. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  97. GRB 250114B: a short GRB detected with INTEGRAL
  98. EP250108a: correction to GCN 38908
  99. GRB 250114A: Enhanced Swift-XRT position
  100. GRB 250113A: INTEGRAL/SPI-ACS 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