Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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"

3759 results found.

  1. LIGO/Virgo S230620al: Global MASTER-Net observations report
  2. LIGO/Virgo S230619bg: Global MASTER-Net observations report
  3. GRB 230618A: Osservatorio Astronomico Nastro verde upper limit
  4. LIGO/Virgo S230618y: Global MASTER-Net observations report
  5. LIGO/Virgo S230618r: Global MASTER-Net observations report
  6. LIGO/Virgo S230616aa: Global MASTER-Net observations report
  7. LIGO/Virgo S230618k: Global MASTER-Net observations report
  8. LIGO/Virgo S230617aj: Global MASTER-Net observations report
  9. LIGO/Virgo S230608ah: Global MASTER-Net observations report
  10. Fermi GRB 230603A: Global MASTER-Net observations report
  11. LIGO/Virgo S230529ay: Global MASTER-Net observations report
  12. LIGO/Virgo S230525a: Global MASTER-Net observations report
  13. LIGO/Virgo/KAGRA S230518h: No transient candidates in CALET observations
  14. Fermi trigger No 706536788: Global MASTER-Net observations report
  15. LIGO/Virgo S230522a: Global MASTER-Net observations report
  16. LIGO/Virgo S230521k: Global MASTER-Net observations report
  17. LIGO/Virgo S230520ae: Global MASTER-Net observations report
  18. IPN triangulation of GRB 230518A (short)
  19. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  20. GRB 230520A: MAXI/GSC detection
  21. LIGO/Virgo S230518h: Global MASTER-Net observations report
  22. GRB 230510B: Fermi GBM detection
  23. GRB 230512A: Kitab possible afterglow candidate
  24. GRB 230512A: Swift-XRT observations
  25. GRB 230512A: GIT optical follow-up ZTF candidates
  26. GRB 230511C: Fermi GBM Final Localization
  27. GRB 230510B: MAXI/GSC detection
  28. Fermi trigger No 705413051: Global MASTER-Net observations report
  29. GRB 230510A: Swift detection of a burst
  30. GRB 230506C: Swift-BAT refined analysis
  31. GRB 230427A: OHP/T193 spectroscopy observations of WISEA J101316.01+481158.7
  32. Fermi trigger No 704365743: Global MASTER-Net observations report
  33. GRB 230428A: Fermi GBM Final Real-time Localization
  34. GRB 230427A: GMG upper limit
  35. GRB 230426A: MASTER OT J023135.16-792104.8 optical counterpart discovery
  36. GRB 230426A: Fermi GBM Detection
  37. GRB 230426A: Fermi GBM Final Real-time Localization
  38. GRB 230420A: MITSuME Akeno optical observation
  39. GRB 230420A: LCOGT Optical Upper Limit
  40. IPN triangulation of GRB 230418A (short)
  41. GRB 230414B: Osservatorio Astronomico Nastro Verde - Sorrento: optical observations
  42. Fermi GRB 230414A: Global MASTER-Net observations report
  43. Fermi trigger No 702745263: Global MASTER-Net observations report
  44. IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube
  45. GRB 230307A: short mininum variability timescale compatible with a merger origin
  46. GRB 230328B: Multa observatory optical afterglow observation
  47. Fermi GRB 230402A: Global MASTER-Net observations report
  48. IceCube-Cascade 230329A: Upper limits from a search for additional neutrino events in IceCube
  49. GRB 230328B: 3.6m DOT multiband optical observation
  50. GRB 230328B: GRBAlpha detection
  51. GRB 230328B NUTTelA-TAO / BSTI Early Measurements
  52. GRB 230328B: OHP/T120 optical observations
  53. GRB 230328B: GIT optical follow-up
  54. GRB 230328B: Nanshan/NEXT optical upper limit
  55. GRB 230328B: AstroSat CZTI detection
  56. GRB 230328B: Fermi GBM observation
  57. GRB 230328B: Mondy, AbAO and Kitab optical observations
  58. GRB 230328B: Mondy optical afterglow confirmation
  59. GRB 230328B: Fermi GBM Final Real-time Localization
  60. Fermi GRB 230328A: Global MASTER-Net observations report
  61. GRB 230328A: Fermi GBM Final Real-time Localization
  62. Fermi trigger No 701313046: Global MASTER-Net observations report
  63. Konus-Wind detection of GRB 230304B
  64. Fermi trigger No 701071944: Global MASTER-Net observations report
  65. GRB 230314A: TURBO Optical Upper Limit
  66. Fermi GRB 230314A: Global MASTER-Net observations report
  67. Further improved IPN localization for GRB 230307A
  68. GRB 230307A: SOAR/Goodman detection of the possible host galaxy
  69. GRB 230228A: NUTTelA-TAO / BSTI Optical Limits
  70. Fermi GRB 230307A: Global MASTER-Net observations report
  71. Konus-Wind detection of GRB 230307A
  72. GRB 230228A: VIRT Optical Upper Limit
  73. GRB 230307A: VZLUSAT-2 detection
  74. GRB 230304B: Detection by GRBAlpha
  75. GRB 230301B: Fermi GBM Final Real-time Localization
  76. GRB 230228A: Fermi GBM Observation
  77. Fermi trigger No 699294715: Global MASTER-Net observations report
  78. GRB 230228A: OSN optical upper limit
  79. Fermi trigger No 699311646: Global MASTER-Net observations report
  80. GRB 230228A: Mondy optical upper limit
  81. GRB 230228A: Enhanced Swift-XRT position
  82. GRB 230228A: Nanshan/NEXT optical upper limit
  83. GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
  84. GRB 230228A: Prompt enhanced Swift-XRT position
  85. GRB 230228A: Swift detection of a possibly short burst
  86. Fermi GRB 230227A: Global MASTER-Net observations report
  87. Fermi trigger No 699029364: Global MASTER-Net observations report
  88. GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
  89. GRB 230205A: VLA radio afterglow confirmation
  90. GRB 230220A: Correction to GCN 33352
  91. GRB 230217A: 6 GHz VLA observations
  92. GRB 230220A: MAXI/GSC detection
  93. GRB 230217A: Swift-XRT observations
  94. IceCube Alert 230217.87: Global MASTER-Net observations report
  95. Fermi trigger No 697678542: Global MASTER-Net observations report
  96. GRB 230205A: 6 GHz VLA observations
  97. GRB 230209A is not a GRB
  98. GRB 230205A: SUBARU HSC pre-imaging for host galaxy search
  99. GRB 230209A: Fermi GBM Final Real-time Localization
  100. GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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