Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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"

6405 results found.

  1. GRB 210218A: Swift-XRT observations
  2. GRB 210217A: Swift-XRT refined Analysis
  3. GRB 210205A: observations with the 3.6m DOT, a potential dark burst?
  4. Fermi/GBM observation of a burst from SGR 1830-0645
  5. GRB 210210A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
  6. GRB 210212A: Swift-XRT refined Analysis
  7. GRB 210204A: observations with the 3.6m Devasthal Optical Telescope and possible jet break
  8. GRB 210211A: Swift-XRT refined Analysis
  9. GRB 210211A: Fermi GBM observation
  10. Swift-XRT observations of IceCube-210210A
  11. Fermi-LAT Gamma-ray Observations of IceCube-210210A
  12. IceCube-210210A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  13. GRB 210210A: Swift-XRT refined Analysis
  14. GRB 210208A: GIT optical upper limit
  15. GRB 210209A: Swift-XRT refined Analysis
  16. GRB 210207B: Swift-XRT refined Analysis
  17. Konus-Wind detection of GRB 210204A (correction to GCN 29415)
  18. Konus-Wind detection of GRB 210204A / ZTF21aagwbjr
  19. GRB 210204A: Optical Observations from HCT
  20. GRB 210204A / ZTF21aagwbjr: Swift-XRT observations
  21. GRB 210205A: Swift-XRT refined Analysis
  22. GRB 210204: Fermi GBM observation
  23. GRB 210202A: Fermi GBM detection
  24. GRB 210202A: Fermi-LAT detection
  25. Continued Chandra observations of GW170817 at ~3.3 years since merger
  26. GRB 140330A: Swift-XRT refined Analysis
  27. GRB 140320B: Swift-XRT refined Analysis
  28. GRB 140402A: Swift-XRT refined Analysis
  29. GRB 140104B: Swift-XRT refined Analysis
  30. ZTF21aaeyldq: Observations with the 3.6m DOT
  31. GRB 210120A: Fermi GBM detection
  32. IPN triangulation of GRB 210124B (short)
  33. GRB 210120A : 1.3m DFOT optical observations
  34. GRB 210112A: 3.6m DOT optical detection
  35. GRB 210119A: Fermi GBM observation
  36. Correction to GCN 29288: NuEm-210111A: No counterpart candidates in INTEGRAL SPI-ACS observation
  37. GRB 201221D: near-infrared observation with LBT
  38. ZTF21aaeyldq: observations with the 3.6m Devasthal Optical Telescope
  39. GRB 210112A: Swift-XRT refined Analysis
  40. NuEm-210111A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  41. Correction to GCN 29278: GRB 201216C XRT refined analysis
  42. GRB 201216C: Swift-XRT refined Analysis
  43. GRB 210102B: further Swift-XRT observations
  44. GRB 210104A: iTelescope optical upper limit
  45. GW170817: HST observations at 3.4 years from merger
  46. GRB 210104A: Swift-XRT refined Analysis
  47. GRB 210104B: Swift-XRT refined Analysis
  48. GRB 210104A: DOAO optical afterglow observations
  49. GRB 210104A: Nanshan/NEXT optical powerlaw decay
  50. GRB 210104A: Fermi GBM detection
  51. GRB 210102B: Swift-XRT observations
  52. GRB 210102C: Fermi GBM detection
  53. GRB 201227A: Chilescope optical observations, possible optical counterpart
  54. GRB 201227A: GRAWITA VST-ESO PARANAL observations
  55. GRB 201227A: Fermi GBM observation
  56. GRB 201229A: SAO RAS optical observations
  57. GRB 201227A: Swift-XRT observations
  58. GRB 201229A: Swift-XRT refined Analysis
  59. GRB 201104B: Maidanak and CrAO optical observations
  60. GRB 201223A: 1.3m DFOT and 1.04m ST optical observations
  61. GRB 201223A: Swift-XRT refined Analysis
  62. GRB 201223A: GROWTH-India Telescope (GIT) photometric follow-up.
  63. GRB 201223A: iTelescope optical afterglow observations
  64. GRB 201223A: Fermi GBM Detection
  65. Swift-XRT observations of Icecube 201222A
  66. IceCube-201222A: No significant detection in HAWC
  67. IceCube-201221A: No significant detection in HAWC
  68. GRB 201221A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
  69. GRB 201221D: Fermi GBM detection
  70. Swift Trigger 1014012 (possible GRB 201221C) is likely not an astrophysical event
  71. GRB 201216A - further Swift-XRT observations
  72. Fermi-LAT Gamma-ray Observations of IceCube-201222A
  73. Fermi-LAT Gamma-ray Observations of IceCube-201221A
  74. IceCube-201222A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  75. GRB 201221D: Swift-XRT refined Analysis
  76. GRB 201221A: Swift/UVOT Upper Limits
  77. GRB 201221A: Swift-XRT refined Analysis
  78. IceCube-201221A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  79. GRB 201214A: Swift-XRT afterglow detection
  80. GRB 201214A: 1.3m DFOT, optical upper limits
  81. GRB201216C: No significant detection in HAWC
  82. GRB 201216C: Fermi-LAT upper limit
  83. GRB 201216C: Fermi GBM detection
  84. GRB 201216A: Fermi GBM detection
  85. GRB 201216A: Swift-XRT observations
  86. Chandra observations of GW170817 at ~3.3 years since merger (Full report)
  87. GRB 201214B: Swift-XRT observations
  88. GRB 201214A: Swift-XRT observations
  89. IceCube-201209: No significant detection in HAWC
  90. Potential X-ray KN afterglow from Chandra observations of GW170817 ~3.3 years since merger (3 Epochs of 4)
  91. Long-lasting X-ray emission from GW170817 detected by Chandra
  92. GRB 201203A: 1.3m DFOT, optical upper limits
  93. Fermi-LAT Gamma-ray Observations of IceCube-201209A
  94. Chandra observations of GW170817 at ~3.3 years since merger (Observation 1 of 4)
  95. GRB 201208A: Swift-XRT afterglow detection
  96. GRB 201208A: Fermi GBM observation
  97. IceCube-201209A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  98. GRB 201209A: Swift-XRT refined Analysis
  99. GRB 201208A: Fermi-LAT detection
  100. Swift follow-up observations of the flat spectrum radio quasar PMN J0206-1150 in the error region of IceCube-201130A

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