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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"

31632 results found.

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

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