Skip to main content
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. 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').
  1. GRB 240726A: AstroSat CZTI detection of a short burst
  2. IceCube-240725A: Upper limits from a search for additional neutrino events in IceCube
  3. GRB 240726A: Fermi GBM Final Real-time Localization
  4. Fermi-LAT gamma-ray observations of IceCube-240725A
  5. IceCube Alert 240725.22: Global MASTER-Net observations report
  6. IceCube-240725A - IceCube observation of a high-energy neutrino candidate track-like event
  7. Swift Trigger 1244778 is not a GRB
  8. Swift GRB240725.11: Global MASTER-Net observations report
  9. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  10. GRB 240720A: Swift-BAT refined analysis
  11. IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
  12. Fermi trigger No 743418632: Global MASTER-Net observations report
  13. Fermi trigger No 743315411: Global MASTER-Net observations report
  14. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  15. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  16. Fermi trigger No 743345551: Global MASTER-Net observations report
  17. Fermi-LAT gamma-ray observations of IceCube-240721A
  18. Fermi Gamma-ray Burst Monitor trigger 743271526/240721680 is not a GRB
  19. Fermi trigger No 743219692: Global MASTER-Net observations report
  20. IceCube-240721A - IceCube observation of a high-energy neutrino candidate track-like event
  21. IceCube Alert 240721.68: Global MASTER-Net observations report
  22. Fermi Gamma-ray Burst Monitor trigger 743243582/240721356 (GRB 240721A) is not a GRB
  23. GRB 240720B: SVOM/GRM observation
  24. GRB 240721A: Fermi GBM Final Real-time Localization
  25. GRB 240720B: AstroSat CZTI detection of a short burst
  26. Fermi GRB 240720A: Global MASTER-Net observations report
  27. GRB 240720A: AstroSat CZTI detection
  28. GRB 240720A: Fermi GBM observation
  29. GRB 240720A: Swift detection of a burst
  30. Swift GRB240720.02: Global MASTER-Net observations report
  31. Konus-Wind detection of GRB 240718A
  32. GRB 240713A: SVOM/GRM observation
  33. Fermi GRB 240718A: Global MASTER-Net observations report
  34. LAT GRB240718.27: Global MASTER-Net observations report
  35. GRB 240718A: Fermi GBM Observation
  36. IceCube-Cascade 240714A: TRT optical observations on the EP/FXT positions
  37. GRB 240718A: Fermi-LAT Detection
  38. GRB 240718A: SVOM/GRM observation
  39. GRB 240718A: BALROG localization (Fermi Trigger 742976945 / GRB 240718270)
  40. GRB 240718A: Fermi GBM Final Real-time Localization
  41. GRB 240712A: Swift-BAT refined analysis
  42. GRB 240716A: GECAM-B detection of a long burst
  43. SVOM/GRM In-Flight Trigger of GRB 240716A
  44. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  45. GRB 240713A: 2.2m CAHA optical limit
  46. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  47. GRB 240715A: Swift/UVOT observations of the XRT sources.
  48. GRB 240715A: Swift-XRT observations
  49. GRB240713A: Swift/UVOT Upper LImits
  50. EP240708a: X-ray follow-up observations with Swift/XRT
  51. GRB 240715A: GECAM-C detection of a short burst
  52. Konus-Wind detection of GRB 240715A
  53. LIGO/Virgo/KAGRA S240716b: Updated Sky localization
  54. GRB 240713A: Swift-XRT observations
  55. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  56. GRB 240712A: Swift-XRT refined Analysis
  57. SVOM/GRM In-Flight Trigger of GRB 240715A
  58. GRB 240713A: LAST optical upper limit
  59. LIGO/Virgo/KAGRA S240716b: Identification of a GW compact binary merger candidate
  60. GRB 240715A: Swift ToO observations
  61. Fermi GRB 240715A: Global MASTER-Net observations report
  62. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  63. GRB 240715A: Fermi GBM Observation
  64. GRB 240712A ATCA radio observations
  65. GRB240715A: GRANDMA Optical Upper Limits
  66. IPN triangulation of GRB 240715A (short)
  67. GW s240422ed: Swift UVOT follow-up
  68. GRB 240712A: Swift/UVOT Upper Limits
  69. EP-WXT flaring star and the optical flaring activity during its decay phase
  70. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  71. The EP-WXT source triggered on July 14th is likely a flaring star
  72. GRB 240715A: Fermi GBM Final Real-time Localization
  73. GRB 240713A: Tiled Swift observations
  74. GRB 240713A: J-band upper limit from WINTER
  75. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  76. GRB 240713A: JinShan optical upper limits
  77. GRB 240713A: OHP/T120 optical upper limit
  78. GRB240713A: X-ray follow-up observation with EP-FXT (duplicate submission of GCN 36859)
  79. GRB240713A: X-ray follow-up observation with EP-FXT
  80. GRB 240713B: AstroSat CZTI detection of a long burst
  81. GRB240713A: Optical upper limit with Kinder observations
  82. Fermi Sub-threshold Observation of GRB240713A
  83. GRB240713A: TAROT and GRANDMA Observations of SVOM/ECLAIRs GRB240713A
  84. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  85. Fermi Gamma-ray Burst Monitor trigger 742413075/240711744 is not a GRB
  86. EP240708a: GSP optical upper limit
  87. GRB 240712A: Swift detection of a burst
  88. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  89. GRB 240711A: Fermi GBM Final Real-time Localization
  90. Fermi trigger No 742405878: Global MASTER-Net observations report
  91. LIGO/Virgo/KAGRA S240627by: Updated Sky localization and EM Bright Classification
  92. Fermi trigger No 742317942: Global MASTER-Net observations report
  93. EP240708a: KAIT optical upper limit
  94. Fermi GRB 240710A: Global MASTER-Net observations report
  95. GRB 240710A: Fermi GBM Final Real-time Localization
  96. EP240708a: NOT optical observations
  97. EP240708a: SVOM/C-GFT optical upper limit
  98. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  99. EP240708a: Optical upper limits with Kinder observations
  100. EP240708a: EP-WXT detection of a fast X-ray transient

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