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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"

32508 results found.

  1. GRB 240720B: VZLUSAT-2 detection
  2. GRB 240710A: VZLUSAT-2 detection
  3. EP240806A: Liverpool Telescope optical follow-up observations
  4. EP240806a: Gemini North-GMOS spectroscopic redshift of z = 2.818
  5. GRB 240805B: GIT optical upper limit
  6. EP240806a: KAIT optical observations
  7. GRB 240805B: Swift-BAT refined analysis
  8. GRB 240805A: Swift-BAT refined analysis
  9. EP240804a (GRB 240804B): NOT optical observations
  10. EP240806a: LCOGT optical counterpart detection
  11. Konus-Wind detection of GRB 240802A (EP240802a)
  12. Improved IPN triangulation of GRB 240802A / EP 240802a
  13. Konus-Wind detection of GRB 240805A
  14. GRB 240805B Bassano Bresciano Observatory upper limit
  15. GRB240805A: Fermi GBM Observation
  16. GRB 240805B: JinShan optical afterglow detection
  17. GRB 240804B/EP240804a: Correction to the GRB name in GCN 37071
  18. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  19. Konus-Wind detection of GRB 240804B (a counterpart of EP240804a)
  20. EP240806a: EP-FXT detection of the X-ray emission
  21. GRB 240624B: VZLUSAT-2 detection
  22. GRB 240619C: VZLUSAT-2 detection
  23. EP 240806A: LCO optical observations
  24. GRB 240805B: Optical detection with 1.6m Mephisto
  25. GRB 240805B: NUTTelA-TAO / BSTI Optical Limits
  26. GRB 240805B: Swift/UVOT Upper Limits
  27. GRB 240805A: Swift/UVOT Upper Limits
  28. GRB 240805B: BTA optical afterglow candidate
  29. GRB 240805A: SVOM/GRM observation
  30. GRB 240805B: LCOGT Optical Upper Limits
  31. Swift GRB 240805B: Global MASTER-Net observations report
  32. GRB 240805B: JinShan optical upper limits
  33. EP240801a: BTA BVRI photometry
  34. Fermi GRB 240805A: Global MASTER-Net observations report
  35. Swift GRB 240805A: Global MASTER-Net observations report
  36. GRB 240805A: Fermi-LAT detection
  37. GRB 240805A: INTEGRAL spectral analysis
  38. EP240801a: Continued optical observations at ZTSh (CraO)
  39. EP240804a: VLT/X-shooter spectroscopic redshift
  40. EP240804a: LCOGT optical counterpart detection
  41. GRB 240805A: A long GRB detected by INTEGRAL
  42. EP240804a: NOT optical counterpart detection
  43. EP240802a: correction of EP-WXT trigger time in GCN 37019
  44. Fermi GRB 240804A: Global MASTER-Net observations report
  45. EP240802a: Montarrenti Observatory optical upper limit
  46. IPN triangulation of GRB 240802A / EP 240802a
  47. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  48. EP240802A: Bassano Bresciano Observatory upper limit
  49. GRB 240802A: SVOM/GRM observation
  50. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  51. EP240801a: further SAO RAS optical observations
  52. EP240801a: optical observations at CrAO and AbAO
  53. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  54. EP240801a: Leavitt Observatory optical observations
  55. EP240801a: GTC spectroscopy and absorption redshift
  56. EP240801a: SAO RAS optical observations
  57. GRB 240801B: AstroSat CZTI Updated classification - likely a solar flare
  58. EP240801a: JinShan optical observations
  59. GRB 240727C: SVOM/GRM observation
  60. EP240801a: NOT optical observations
  61. EP240801a: follow-up observation with LCOGT
  62. Fermi GBM trigger 744179961 / 240801194 can not be confirmed as a GRB
  63. GRB 240730A: Swift-BAT refined analysis
  64. EP240801a: GSP follow-up observations of the candidate counterpart
  65. EP240801a: Kinder follow-up observations of the candidate counterpart
  66. EP240708a: Kinder follow-up observations of the candidate counterpart (duplicate submission of GCN 37002)
  67. EP240801a: KAIT optical counterpart observations
  68. EP240801a: GMG observation
  69. EP240801a: TRT optical counterpart detection
  70. Fermi GRB 240801A: Global MASTER-Net observations report
  71. GRB 240731A: Fermi GBM Final Localization
  72. GRB 240730A: Osservatorio Astronomico Nastro Verde upper limit
  73. Fermi GRB 240730B: Global MASTER-Net observations report
  74. Swift GRB 240730A: Global MASTER-Net observations report
  75. GRB 240715A: Swift-XRT afterglow detection
  76. GRB 240730A: KAIT Optical Upper Limit
  77. GRB 240727C: GRBAlpha detection
  78. GRB 240730A: Swift/UVOT Upper Limits
  79. GRB 240727A: Swift-BAT refined analysis
  80. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  81. GRB 240727A: observations of optical counterpart.
  82. GRB 240727B: Swift-XRT observations
  83. Fermi GRB 240727A: Global MASTER-Net observations report
  84. GRB 240727A: Swift/UVOT detection
  85. GRB 240727A: Osservatorio Astronomico Nastro Verde upper limit
  86. GRB 240727A: NOT optical observation
  87. GRB 240727A: JinShan optical upper limits
  88. GRB 240727A Bassano Bresciano Observatory upper limit
  89. GRB 240727D: Correction to the GRB name in GCN 36958
  90. GRB 240720B: GRBAlpha detection
  91. GRB 240718A: GRBAlpha detection
  92. GRB 240627A: GRBAlpha detection
  93. Fermi GRB 240726A: Global MASTER-Net observations report
  94. GRB 240727B: Fermi GBM Observation
  95. GRB240529A: VIRT optical transient detection
  96. GRB 240727B: Swift ToO observations
  97. GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
  98. GRB 240726A: SVOM/GRM observation
  99. GRB240727A: Skynet Optical Afterglow Observations
  100. GRB 240727A: TRT optical afterglow detection

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