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').

22420 results found.

  1. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  2. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  3. GRB 240529A: J-band detections with WINTER
  4. GRB 240529A: Skynet Optical Observations
  5. LXT 240528A: LEIA detection of a fast X-ray transient
  6. GRB 240529A: Swift-BAT refined analysis
  7. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  8. GRB 240529A: Swift-XRT refined Analysis
  9. GRB 240529A: Swift/UVOT Detection
  10. GRB 240529A: NOT optical observations
  11. GRB 240527B: Swift-XRT afterglow detection
  12. GRB 240529A: Enhanced Swift-XRT position
  13. GRB 240529A: Swift detection of a burst with an optical counterpart
  14. LIGO/Virgo/KAGRA S240527fv: Updated Sky localization
  15. GRB 240527B: Fermi GBM Observation
  16. LIGO/Virgo/KAGRA S240527fv: Identification of a GW compact binary merger candidate
  17. LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate
  18. GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
  19. GRB 240523A: Swift-BAT refined analysis
  20. LIGO/Virgo/KAGRA S240525p: Updated Sky localization
  21. LIGO/Virgo/KAGRA S240525p: Identification of a GW compact binary merger candidate
  22. GRB 240523A: Swift-XRT refined Analysis
  23. GRB 240523A: Enhanced Swift-XRT position
  24. GRB 240523A: Swift detection of a burst
  25. GRB 240521B: Fermi GBM Observation
  26. Fermi GBM Sub-Threshold Detection of GRB 240516B
  27. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  28. LIGO/Virgo/KAGRA S240520cv: Updated Sky localization and EM Bright Classification
  29. EP240518a: GSP optical upper limit
  30. GRB 240521A: GECAM-B detection of a long burst
  31. GRB 240516B: AstroSat CZTI detection
  32. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  33. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  34. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  35. LIGO/Virgo/KAGRA S240520cv: Identification of a GW compact binary merger candidate
  36. IceCube-Cascade 240518A: Upper limits from a search for additional neutrino events in IceCube
  37. GRB 240514B: VZLUSAT-2 detection
  38. GRB 240504A: VZLUSAT-2 detection
  39. GRB 240502A: VZLUSAT-2 detection
  40. GRB 240516A: Swift/UVOT Upper Limits
  41. EP240518a: possibly identified with a flare star by EP-FXT
  42. GRB 240519A: BALROG localization (Fermi Trigger 737788024 / GRB 240519213)
  43. EP240518a: EP-WXT detection of a new X-ray transient
  44. LIGO/Virgo/KAGRA S240514c: Updated Sky localization
  45. GRB 240516A: Swift-BAT refined analysis
  46. IPN triangulation of GRB 240514B (short)
  47. GRB 240516A: Swift-XRT refined Analysis
  48. GRB 240516A: Fermi GBM Observation
  49. GRB 240511A: Observations from GTC/OSIRIS+
  50. GRB 240516A: Swift detection of a burst
  51. GRB 240511A: radio detection of afterglow candidate
  52. MAXI GRB240514.78: Global MASTER-Net observations report
  53. GRB 240514E: MAXI/GSC detection of a probable afterglow
  54. LIGO/Virgo/KAGRA S240514x: Updated Sky localization
  55. LIGO/Virgo/KAGRA S240515m: Identification of a GW compact binary merger candidate
  56. GRB 240513A: Fermi GBM observation
  57. GRB 240513A: Swift-XRT observations
  58. LIGO/Virgo/KAGRA S240513ei: Updated Sky localization
  59. LIGO/Virgo/KAGRA S240514x: Identification of a GW compact binary merger candidate
  60. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate
  61. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  62. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  63. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  64. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  65. LIGO/Virgo/KAGRA S240513ei: Identification of a GW compact binary merger candidate
  66. GRB 240511A: Fermi GBM Observation
  67. GRB 240511A: Swift-BAT refined analysis
  68. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  69. GRB 240511A: J-band observations with WINTER
  70. Fermi trigger No 737247400: Global MASTER-Net observations report
  71. Fermi trigger No 737168073: Global MASTER-Net observations report
  72. GRB 240511A: Enhanced Swift-XRT position
  73. GRB 240511A : MITSuME Akeno optical upper limits
  74. LIGO/Virgo/KAGRA S240512r: Updated Sky localization and EM Bright Classification
  75. GRB 240511A: Swift-XRT refined Analysis
  76. LIGO/Virgo/KAGRA S240512r: Identification of a GW compact binary merger candidate
  77. GRB 240511A: Swift detection of a burst
  78. LIGO/Virgo/KAGRA S240511i: Updated Sky localization
  79. Fermi trigger No 737111207: Global MASTER-Net observations report
  80. LIGO/Virgo/KAGRA S240511i: Identification of a GW compact binary merger candidate
  81. LIGO/Virgo/KAGRA S240422ed: GMOS-S photometry of J-GEM24a
  82. LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
  83. LIGO/Virgo/KAGRA S240422ed: Candidates from the latest GW-MMADS DECam Observations
  84. EP240506a: Xinglong optical upper limit
  85. GRB 240504A: Fermi GBM Observation
  86. EP240506a: Archival radio searching
  87. EP240506a: TRT optical upper limit
  88. LIGO/Virgo/KAGRA S240507p: Updated Sky localization and EM Bright Classification
  89. LIGO/Virgo/KAGRA S240422ed: Upper limits from a two-week IceCube neutrino search
  90. EP240506a: Optical upper limit with Kinder observations
  91. IPN triangulation of GRB 240504A
  92. GRB 240502A: 1.3m DFOT Optical upper limit
  93. EP240506a: EP-WXT detection of a new fast X-ray transient
  94. LIGO/Virgo/KAGRA S240507p: Identification of a GW compact binary merger candidate
  95. LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations
  96. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  97. LIGO/Virgo/KAGRA S240505av: Updated Sky localization and EM Bright Classification
  98. LIGO/Virgo/KAGRA S240505av: Identification of a GW compact binary merger candidate
  99. Fermi trigger No 736461232: Global MASTER-Net observations report
  100. GW170817: VLA observations at ~5.5 yrs since merger

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