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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"

32531 results found.

  1. GRB 240808A: AstroSat CZTI detection
  2. GRB 240809A: GIT afterglow observations
  3. GRB 240809A: Swift/UVOT Detection
  4. GRB 240809A: Tentative redshift from NOT
  5. IPN triangulation of GRB 240807A / EP 240807a
  6. LIGO/Virgo/KAGRA S240807h: Updated Sky localization and EM Bright Classification
  7. X-ray Transient EP240807a: PRIME near-infrared upper limits
  8. Swift GRB 240809A: Global MASTER-Net observations report
  9. GRB 240809A: JinShan optical observations
  10. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  11. GRB 240809A: SVOM/GRM observation
  12. GRB 240807A: SVOM/GRM observation
  13. EP-WXT trigger 01709018832: SVOM/C-GFT observations of the star flare
  14. EP240807a: STEP/T80S optical limits
  15. GRB 240807B: AstroSat CZTI detection of a short burst
  16. EP EP240807a: Global MASTER-Net observations report
  17. EP EP240806a: Global MASTER-Net observations report
  18. GRB 240801A: GRBAlpha detection
  19. GRB 240710B: VZLUSAT-2 detection
  20. GRB 240805A: ATCA Radio Upper Limits
  21. EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
  22. S240807h: Identification of a GW compact binary merger candidate
  23. EP240802a/GRB240802A: KAIT optical upper limit
  24. GRB 240720B: VZLUSAT-2 detection
  25. GRB 240710A: VZLUSAT-2 detection
  26. EP240806A: Liverpool Telescope optical follow-up observations
  27. EP240806a: Gemini North-GMOS spectroscopic redshift of z = 2.818
  28. GRB 240805B: GIT optical upper limit
  29. EP240806a: KAIT optical observations
  30. GRB 240805B: Swift-BAT refined analysis
  31. GRB 240805A: Swift-BAT refined analysis
  32. EP240804a (GRB 240804B): NOT optical observations
  33. EP240806a: LCOGT optical counterpart detection
  34. Konus-Wind detection of GRB 240802A (EP240802a)
  35. Improved IPN triangulation of GRB 240802A / EP 240802a
  36. Konus-Wind detection of GRB 240805A
  37. GRB 240805B Bassano Bresciano Observatory upper limit
  38. GRB240805A: Fermi GBM Observation
  39. GRB 240805B: JinShan optical afterglow detection
  40. GRB 240804B/EP240804a: Correction to the GRB name in GCN 37071
  41. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  42. Konus-Wind detection of GRB 240804B (a counterpart of EP240804a)
  43. EP240806a: EP-FXT detection of the X-ray emission
  44. GRB 240624B: VZLUSAT-2 detection
  45. GRB 240619C: VZLUSAT-2 detection
  46. EP 240806A: LCO optical observations
  47. GRB 240805B: Optical detection with 1.6m Mephisto
  48. GRB 240805B: NUTTelA-TAO / BSTI Optical Limits
  49. GRB 240805B: Swift/UVOT Upper Limits
  50. GRB 240805A: Swift/UVOT Upper Limits
  51. GRB 240805B: BTA optical afterglow candidate
  52. GRB 240805A: SVOM/GRM observation
  53. GRB 240805B: LCOGT Optical Upper Limits
  54. Swift GRB 240805B: Global MASTER-Net observations report
  55. GRB 240805B: JinShan optical upper limits
  56. EP240801a: BTA BVRI photometry
  57. Fermi GRB 240805A: Global MASTER-Net observations report
  58. Swift GRB 240805A: Global MASTER-Net observations report
  59. GRB 240805A: Fermi-LAT detection
  60. GRB 240805A: INTEGRAL spectral analysis
  61. EP240801a: Continued optical observations at ZTSh (CraO)
  62. EP240804a: VLT/X-shooter spectroscopic redshift
  63. EP240804a: LCOGT optical counterpart detection
  64. GRB 240805A: A long GRB detected by INTEGRAL
  65. EP240804a: NOT optical counterpart detection
  66. EP240802a: correction of EP-WXT trigger time in GCN 37019
  67. Fermi GRB 240804A: Global MASTER-Net observations report
  68. EP240802a: Montarrenti Observatory optical upper limit
  69. IPN triangulation of GRB 240802A / EP 240802a
  70. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  71. EP240802A: Bassano Bresciano Observatory upper limit
  72. GRB 240802A: SVOM/GRM observation
  73. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  74. EP240801a: further SAO RAS optical observations
  75. EP240801a: optical observations at CrAO and AbAO
  76. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  77. EP240801a: Leavitt Observatory optical observations
  78. EP240801a: GTC spectroscopy and absorption redshift
  79. EP240801a: SAO RAS optical observations
  80. GRB 240801B: AstroSat CZTI Updated classification - likely a solar flare
  81. EP240801a: JinShan optical observations
  82. GRB 240727C: SVOM/GRM observation
  83. EP240801a: NOT optical observations
  84. EP240801a: follow-up observation with LCOGT
  85. Fermi GBM trigger 744179961 / 240801194 can not be confirmed as a GRB
  86. GRB 240730A: Swift-BAT refined analysis
  87. EP240801a: GSP follow-up observations of the candidate counterpart
  88. EP240801a: Kinder follow-up observations of the candidate counterpart
  89. EP240708a: Kinder follow-up observations of the candidate counterpart (duplicate submission of GCN 37002)
  90. EP240801a: KAIT optical counterpart observations
  91. EP240801a: GMG observation
  92. EP240801a: TRT optical counterpart detection
  93. Fermi GRB 240801A: Global MASTER-Net observations report
  94. GRB 240731A: Fermi GBM Final Localization
  95. GRB 240730A: Osservatorio Astronomico Nastro Verde upper limit
  96. Fermi GRB 240730B: Global MASTER-Net observations report
  97. Swift GRB 240730A: Global MASTER-Net observations report
  98. GRB 240715A: Swift-XRT afterglow detection
  99. GRB 240730A: KAIT Optical Upper Limit
  100. GRB 240727C: GRBAlpha detection

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