Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. 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"

6173 results found.

  1. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  2. GRB 240819A: Swift-XRT observations
  3. EP240820a: EP detection of a fast X-ray transient
  4. GRB 240819A: X-ray follow-up observation with EP-FXT
  5. EP240816b: TRT optical upper limit
  6. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  7. Konus-Wind detection of GRB 240811A
  8. GRB 240811A: Swift-XRT refined Analysis
  9. Konus-Wind detection of GRB 240809A
  10. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  11. Fermi-LAT gamma-ray observations of IceCube-240808A
  12. GRB 240809A: GIT afterglow observations
  13. GRB 240809A: Tentative redshift from NOT
  14. GRB 240809A: Swift-XRT refined Analysis
  15. GRB 240809A: JinShan optical observations
  16. The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
  17. EP240806a: Gemini North-GMOS spectroscopic redshift of z = 2.818
  18. EP240804a (GRB 240804B): NOT optical observations
  19. EP240806a: LCOGT optical counterpart detection
  20. GRB240805A: Fermi GBM Observation
  21. Konus-Wind detection of GRB 240804B (a counterpart of EP240804a)
  22. GRB 240805B: Swift-XRT refined Analysis
  23. GRB 240805A: Swift-XRT refined Analysis
  24. GRB 240805A: Fermi-LAT detection
  25. EP240804a: LCOGT optical counterpart detection
  26. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  27. EP240801a: further SAO RAS optical observations
  28. EP240801a: SAO RAS optical observations
  29. EP240801a: follow-up observation with LCOGT
  30. EP240801a: Kinder follow-up observations of the candidate counterpart
  31. EP240801a: TRT optical counterpart detection
  32. GRB 240730A: Swift-XRT refined Analysis
  33. GRB 240715A: Swift-XRT afterglow detection
  34. GRB 240730A: Swift detection of a burst
  35. GRB 240727B: Swift-XRT observations
  36. GRB 240727A: Swift-XRT refined Analysis
  37. GRB 240727B: Fermi GBM Observation
  38. GRB 240727A: TRT optical afterglow detection
  39. Fermi-LAT gamma-ray observations of IceCube-240725A
  40. Fermi-LAT gamma-ray observations of IceCube-240721A
  41. GRB 240720A: Fermi GBM observation
  42. GRB 240718A: Fermi GBM Observation
  43. GRB 240718A: Fermi-LAT Detection
  44. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  45. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  46. GRB 240715A: Swift/UVOT observations of the XRT sources.
  47. GRB 240715A: Swift-XRT observations
  48. GRB240713A: Swift/UVOT Upper LImits
  49. GRB 240715A: GECAM-C detection of a short burst
  50. GRB 240713A: Swift-XRT observations
  51. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  52. GRB 240712A: Swift-XRT refined Analysis
  53. GRB 240715A: Fermi GBM Observation
  54. The EP-WXT source triggered on July 14th is likely a flaring star
  55. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  56. GRB240713A: X-ray follow-up observation with EP-FXT
  57. GRB 240713B: AstroSat CZTI detection of a long burst
  58. GRB240713A: Optical upper limit with Kinder observations
  59. EP240708a: NOT optical observations
  60. EP240708a: Optical upper limits with Kinder observations
  61. EP240703c: Kinder optical follow-up and Swift XRT observations
  62. EP240703a: Kinder optical follow-up observations
  63. EP240703c: EP-WXT detection of an X-ray transient
  64. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  65. EP240703a: EP-WXT detection of a fast X-ray transient
  66. Konus-Wind detection of GRB 240619A
  67. GRB 240625A: Fermi GBM Observation
  68. EP240625a: EP-WXT detection of a fast X-ray transient
  69. GRB240624A: Fermi GBM Observation
  70. X-ray transient EP240618a: Fermi/GBM non-detection
  71. EP240618a: Swift/XRT upper limit
  72. EP240617a: tentative Swift/XRT detection of the afterglow
  73. GRB 240619A: Swift-XRT probable afterglow detection
  74. GRB 240619A: Fermi GBM Observation
  75. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  76. Fermi trigger No 740430582: Global MASTER-Net observations report
  77. GRB240615A: 1.3m DFOT optical upper limit
  78. EP240617a: EP-WXT detection of a fast X-ray transient
  79. GRB 240615A: Fermi GBM Observation
  80. GRB 240615A: Swift-XRT observations
  81. GRB 240615A: FLWO-1.2m optical upper limits
  82. GRB 240607A: Fermi GBM Observation
  83. GRB 240606B: Fermi GBM Observation
  84. GRB 240607A: Fermi GBM detection of a very bright burst
  85. GRB 240606B: Swift-XRT afterglow detection
  86. Swift Trigger 1235109: a possible GRB 240606A
  87. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  88. Swift Trigger 1232465: consistent with noise
  89. GRB 240529A: continued SAO RAS optical observations
  90. GRB 240529A: OSN optical detection
  91. The EP-WXT source triggered on June 1st is likely a flaring star
  92. GRB 240529A: further SAO RAS optical observations
  93. GRB 240529A: 1.3m DFOT Optical observations
  94. Konus-Wind detection of GRB 240529A
  95. IPN triangulation of the initial episode of GRB 240529A
  96. GRB 240529A: SAO RAS optical observations
  97. GRB 240529A: optical photometry from Konkoly
  98. GRB 240529A: Swift-XRT refined Analysis
  99. GRB 240527B: Swift-XRT afterglow detection
  100. GRB 240527B: Fermi GBM Observation

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