Skip to main content
New! BOOM Notices and Schema v7.0.0. 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"

38258 results found.

  1. GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
  2. GRB 250217C: DDOTI Upper Limits on the Optical Afterglow
  3. GRB 250217C: SVOM/GRM observation
  4. GRB 250217C: Tiled Swift observations
  5. GRB 250217C: Fermi GBM Observation
  6. GRB 250215A / EP250215A: Encouraging Follow-up Observations of a BdHN I with a Rest-Frame Duration 2.3 s at z=4.61
  7. IPN triangulation of GRB 250217C (short)
  8. SVOM/sb25021804: SVOM detection of a long X-ray transient
  9. GRB 250213A: Swift-XRT observations
  10. LIGO/Virgo/KAGRA S250206dm: AZT-33IK Target Optical Observations
  11. GRB 250216A: AstroSat CZTI detection
  12. GRB 250217C: AstroSat CZTI detection of a short burst
  13. Fermi GRB 250217C: Global MASTER-Net observations report
  14. GRB 250217C: Fermi GBM Final Real-time Localization
  15. LIGO/Virgo/KAGRA S250206dm: observation in AbAO, optical transient near NED/GLADE+ galaxy WISEA J021210.14+514821.7
  16. Fermi GRB 250217A: Global MASTER-Net observations report
  17. GRANDMA/OPD observations of GRB250215A
  18. GRB 250217B: Fermi GBM Final Real-time Localization
  19. GRB 250217A: Fermi GBM Final Real-time Localization
  20. Fermi GRB 250216A: Global MASTER-Net observations report
  21. GRB 250215A / EP250215a: LCO detection of the afterglow
  22. GRB 250216A: Fermi GBM Final Real-time Localization
  23. GRB 250215A: Swift/UVOT Upper Limits
  24. GRB 250215A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  25. EP250215a / GRB 250215A : GTC redshift z = 4.61
  26. GRB 250215A: Fermi GBM Observation
  27. EP250215a / GRB 250215A : NOT optical observations
  28. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  29. GRB 250215A / EP250215a: Gemini-South optical observation of a likely rebrightening
  30. GRB 250213A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  31. GRB 250215A: Swift-XRT refined Analysis
  32. GRB 250215A: SVOM/GRM observation
  33. EP250215a / GRB 250215A: AstroSat CZTI detection
  34. GRB 250215A / EP250215a: SVOM/VT optical candidate comfirmation
  35. EP250215a: Global MASTER-Net observations report
  36. EP250215A/GRB 250215A: INTEGRAL SPI-ACS detection
  37. EP250215a / GRB 250215A (potentially): NOT likely optical counterpart
  38. EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
  39. Fermi GRB 250215A: Global MASTER-Net observations report
  40. GRB 250215A: Fermi GBM Final Real-time Localization
  41. Fermi trigger No 761206993: Global MASTER-Net observations report
  42. GRB 250213A：SVOM/VT optical candidate
  43. Fermi Gamma-ray Burst Monitor trigger 761206993/250214266 is not a GRB
  44. EP250207b: Xinglong optical upper limit
  45. Fermi GRB 250214A: Global MASTER-Net observations report
  46. GRB 250213A: Swift ToO observations
  47. GRB 250214A: Fermi GBM Final Real-time Localization
  48. EP250212a: Xinglong optical upper limit
  49. GRB 250213A: SVOM detection of a burst
  50. EP250212a: Global MASTER-Net observations report
  51. GRB 250205A: VIRT Optical Upper Limit
  52. GRB 250205A: Leavitt Observatory optical upper limit
  53. GRB 250210A: GRBAlpha detection
  54. Fermi GRB 250212A: Global MASTER-Net observations report
  55. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  56. Fermi trigger No 760945500: Global MASTER-Net observations report
  57. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  58. GRB 250211B: A long GRB detected by INTEGRAL
  59. LIGO/Virgo/KAGRA S250206dm: GECKO Continued Observaiton with 7DT
  60. GRB 250211A: Swift ToO observations
  61. Integral GRB250211.89: Global MASTER-Net observations report
  62. GRB 250212A: Fermi GBM Final Real-time Localization
  63. GRB 250207A: Fermi GBM Observation
  64. GRB 250206A: Fermi GBM Observation
  65. GRB 250205A / EP250205A: radio detection with the VLA
  66. EP250207b: Tentative z-band brightening source
  67. Konus-Wind detection of GRB 250207A
  68. Konus-Wind detection of GRB 250206A
  69. GRB 250210A: SVOM/GRM observation of a long burst
  70. EP250207b: Liverpool Telescope possible optical counterpart
  71. EP250207b: Global MASTER-Net observations report
  72. Fermi Gamma-ray Burst Monitor trigger 760945500/250211240 is not a GRB
  73. GRB 250207A: Skynet optical afterglow observations
  74. GRB 241128A: VIRT Optical Upper Limit
  75. EP250207A: Upper limits from Fermi-GBM Observations
  76. GRB 250210A: INTEGRAL SPI-ACS detection
  77. GRB 250210A: AstroSat CZTI detection
  78. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  79. Fermi GRB 250210A: Global MASTER-Net observations report
  80. GRB 250210A: Fermi GBM Final Real-time Localization
  81. LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations
  82. LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
  83. IceCube Alert 250207.09: Global MASTER-Net observations report
  84. GRB 250204B: GRBAlpha detection
  85. GRB 250204A: GRBAlpha detection
  86. LIGO/Virgo/KAGRA S250206dm & FRB 20250206A: MASTER observations and possible mother galaxy
  87. GRB 250207A: 1.3m DFOT Optical observations
  88. GRB 250206A: Swift-XRT observations
  89. GRB 250129A: GRANDMA Continued Afterglow Detection
  90. GRB 250207A: Swift-BAT refined analysis
  91. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  92. GRB 250205A: 1.3m DFOT optical upper limit
  93. GRB 250206A: Tiled Swift observations
  94. GRB 250206A: EIRSAT-1 GMOD Detection
  95. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  96. GRB 250206A: Fermi-LAT detection
  97. GRB 250207B: Swift-XRT observations
  98. GRB 250208A: Fermi GBM Final Real-time Localization
  99. GRB 250207A: Swift-XRT refined Analysis
  100. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star

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