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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"

31727 results found.

  1. IPN triangulation of GRB 240807A / EP 240807a
  2. LIGO/Virgo/KAGRA S240807h: Updated Sky localization and EM Bright Classification
  3. X-ray Transient EP240807a: PRIME near-infrared upper limits
  4. Swift GRB 240809A: Global MASTER-Net observations report
  5. GRB 240809A: JinShan optical observations
  6. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  7. GRB 240809A: SVOM/GRM observation
  8. GRB 240807A: SVOM/GRM observation
  9. EP-WXT trigger 01709018832: SVOM/C-GFT observations of the star flare
  10. EP240807a: STEP/T80S optical limits
  11. GRB 240807B: AstroSat CZTI detection of a short burst
  12. EP EP240807a: Global MASTER-Net observations report
  13. EP EP240806a: Global MASTER-Net observations report
  14. GRB 240801A: GRBAlpha detection
  15. GRB 240710B: VZLUSAT-2 detection
  16. GRB 240805A: ATCA Radio Upper Limits
  17. EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
  18. S240807h: Identification of a GW compact binary merger candidate
  19. EP240802a/GRB240802A: KAIT optical upper limit
  20. GRB 240720B: VZLUSAT-2 detection
  21. GRB 240710A: VZLUSAT-2 detection
  22. EP240806A: Liverpool Telescope optical follow-up observations
  23. EP240806a: Gemini North-GMOS spectroscopic redshift of z = 2.818
  24. GRB 240805B: GIT optical upper limit
  25. EP240806a: KAIT optical observations
  26. GRB 240805B: Swift-BAT refined analysis
  27. GRB 240805A: Swift-BAT refined analysis
  28. EP240804a (GRB 240804B): NOT optical observations
  29. EP240806a: LCOGT optical counterpart detection
  30. Konus-Wind detection of GRB 240802A (EP240802a)
  31. Improved IPN triangulation of GRB 240802A / EP 240802a
  32. Konus-Wind detection of GRB 240805A
  33. GRB 240805B Bassano Bresciano Observatory upper limit
  34. GRB240805A: Fermi GBM Observation
  35. GRB 240805B: JinShan optical afterglow detection
  36. GRB 240804B/EP240804a: Correction to the GRB name in GCN 37071
  37. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  38. Konus-Wind detection of GRB 240804B (a counterpart of EP240804a)
  39. EP240806a: EP-FXT detection of the X-ray emission
  40. GRB 240624B: VZLUSAT-2 detection
  41. GRB 240619C: VZLUSAT-2 detection
  42. EP 240806A: LCO optical observations
  43. GRB 240805B: Optical detection with 1.6m Mephisto
  44. GRB 240805B: NUTTelA-TAO / BSTI Optical Limits
  45. GRB 240805B: Swift/UVOT Upper Limits
  46. GRB 240805A: Swift/UVOT Upper Limits
  47. GRB 240805B: BTA optical afterglow candidate
  48. GRB 240805A: SVOM/GRM observation
  49. GRB 240805B: LCOGT Optical Upper Limits
  50. Swift GRB 240805B: Global MASTER-Net observations report
  51. GRB 240805B: JinShan optical upper limits
  52. EP240801a: BTA BVRI photometry
  53. Fermi GRB 240805A: Global MASTER-Net observations report
  54. Swift GRB 240805A: Global MASTER-Net observations report
  55. GRB 240805A: Fermi-LAT detection
  56. GRB 240805A: INTEGRAL spectral analysis
  57. EP240801a: Continued optical observations at ZTSh (CraO)
  58. EP240804a: VLT/X-shooter spectroscopic redshift
  59. EP240804a: LCOGT optical counterpart detection
  60. GRB 240805A: A long GRB detected by INTEGRAL
  61. EP240804a: NOT optical counterpart detection
  62. EP240802a: correction of EP-WXT trigger time in GCN 37019
  63. Fermi GRB 240804A: Global MASTER-Net observations report
  64. EP240802a: Montarrenti Observatory optical upper limit
  65. IPN triangulation of GRB 240802A / EP 240802a
  66. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  67. EP240802A: Bassano Bresciano Observatory upper limit
  68. GRB 240802A: SVOM/GRM observation
  69. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  70. EP240801a: further SAO RAS optical observations
  71. EP240801a: optical observations at CrAO and AbAO
  72. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  73. EP240801a: Leavitt Observatory optical observations
  74. EP240801a: GTC spectroscopy and absorption redshift
  75. EP240801a: SAO RAS optical observations
  76. GRB 240801B: AstroSat CZTI Updated classification - likely a solar flare
  77. EP240801a: JinShan optical observations
  78. GRB 240727C: SVOM/GRM observation
  79. EP240801a: NOT optical observations
  80. EP240801a: follow-up observation with LCOGT
  81. Fermi GBM trigger 744179961 / 240801194 can not be confirmed as a GRB
  82. GRB 240730A: Swift-BAT refined analysis
  83. EP240801a: GSP follow-up observations of the candidate counterpart
  84. EP240801a: Kinder follow-up observations of the candidate counterpart
  85. EP240708a: Kinder follow-up observations of the candidate counterpart (duplicate submission of GCN 37002)
  86. EP240801a: KAIT optical counterpart observations
  87. EP240801a: GMG observation
  88. EP240801a: TRT optical counterpart detection
  89. Fermi GRB 240801A: Global MASTER-Net observations report
  90. GRB 240731A: Fermi GBM Final Localization
  91. GRB 240730A: Osservatorio Astronomico Nastro Verde upper limit
  92. Fermi GRB 240730B: Global MASTER-Net observations report
  93. Swift GRB 240730A: Global MASTER-Net observations report
  94. GRB 240715A: Swift-XRT afterglow detection
  95. GRB 240730A: KAIT Optical Upper Limit
  96. GRB 240727C: GRBAlpha detection
  97. GRB 240730A: Swift/UVOT Upper Limits
  98. GRB 240727A: Swift-BAT refined analysis
  99. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  100. GRB 240727A: observations of optical counterpart.

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