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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"

16159 results found.

  1. GRB 120422A: Gemini observations
  2. GRB 120419A: Swift-XRT and UVOT observations
  3. GRB 120404A: optical observations in Mondy observatory
  4. GRB 120404A: optical observations
  5. GRB 120404A, Optical Observations
  6. GRB 120404A: SMARTS optical/IR observations
  7. GRB120404A: MOA optical observations of the initial rise afterglow
  8. GRB 120404A: VLT/X-shooter redshift confirmation
  9. GRB 120404A: Swift/UVOT Detection
  10. GRB 120404A: MITSuME Ishigakijima Optical Observation
  11. GRB 120404A: MITSuME Okayama Optical Observation
  12. GRB 120404A : TNT optical observation
  13. GRB 120401A: GROND Detection of an optical/NIR afterglow candidate
  14. GRB 120402B: MASTER early OT limit
  15. GRB 120403B: TAROT La Silla observatory optical observations
  16. GRB 120404A: Gemini-N Redshift
  17. GRB 120404A: MITSuME Akeno Optical upper limits
  18. GRB 120404A: MASTER early OT limit
  19. GRB 120404A: Faulkes Telescope North afterglow confirmation
  20. GRB 120404A: Swift detection of a burst with an optical counterpart
  21. GRB 120403B: Swift/UVOT Upper Limits
  22. GRB 120402A: optical upper limit
  23. GRB 120320A: optical upper limit in Mondy observatory
  24. GRB 120320A: early optical upper limit
  25. GRB 120403A: MASTER follow up observations
  26. GRB 120402A: MASTER follow up observations
  27. GRB 120326A: Bassano Bresciano Observatory - correction for GCN Cir 13178
  28. GRB 120326A: Cima Rest and Bassano Brescia
  29. GRB 120327A: SMARTS optical/IR afterglow observations
  30. GRB 120326A: HCT optical observations
  31. GRB 120326A: EVLA Observations
  32. GRB120327A - ATCA radio afterglow detection at 34GHz
  33. GRB 120324A: CrAO optical upper limit
  34. GRB 120326A: Bassano Bresciano Observatory lightcurve analisis
  35. GRB 120326A: MITSuME Ishigakijima Optical Observation at 3 days afterthe burst
  36. GRB 120326A: CARMA 3mm detection
  37. GRB 120326A: Bassano Bresciano Observatory optical observations
  38. GRB 120328A: MITSuME Ishigakijima Optical Upper Limits
  39. GRB 120326A: MITSuME Ishigakijima Optical Observation at 2 days afterthe burst
  40. GRB 120327A: MITSuME Ishigakijima Optical Upper Limits at 1 day afterthe burst
  41. Trigger 518853: Swift detection of a probable Galactic transient
  42. GRB 120327A: Zadko optical observations
  43. GRB 120328A: Swift/UVOT Upper Limits
  44. GRB 120326A: Bassano Bresciano Observatory further optical observations
  45. GRB 120327A: MITSuME Ishigakijima Optical Observation
  46. GRB 120326A: MITSuME Ishigakijima Optical Observation
  47. GRB 120327A: NOT optical observations
  48. GRB 120328A: TAROT La Silla observatory optical observations
  49. GRB 120326A: Xinglong TNT further optical observation��correction for GCN Cir 13149)
  50. GRB 120326A: Xinglong TNT further optical observation
  51. GRB 120327A: GTC redshift confirmation
  52. GRB 120327A afterglow detection
  53. GRB 120326A: PAIRITEL NIR Observations
  54. GRB 120326A: Bassano Bresciano Observatory optical observations
  55. GRB 120326A: LOAO R-band Observations
  56. GRB 120326A : SMA submm observation
  57. GRB 120327A: X-shooter redshift
  58. GRB 120327A: Gemini-South redshift
  59. GRB 120327A: TAROT La Silla observatory optical decay
  60. GRB120326A: TNT optical observation
  61. GRB 120327A: IAC80 I-band observations
  62. GRB 120327A: REM NIR and optical observations
  63. GRB 120326A: Maisoncelles Observatory optical observations
  64. GRB 120327A: Liverpool Telescope Observations
  65. GRB 120327A: TAROT La Silla observatory optical detection
  66. GRB 120327A: Swift detection of a burst with an optical counterpart
  67. GRB 120326A: optical observation of GMG
  68. GRB 120326A : LOT optical observation
  69. GRB 120326A: T17 optical observations
  70. GRB 120326A: GTC redshift
  71. GRB 120323A: MASTER follow up observations
  72. GRB 120326A: Optical observations at Crni Vrh
  73. GRB120326A: IAC80 observations
  74. GRB 120326A: Liverpool Telescope observations
  75. Skynet/Dolomiti Observations of GRB120326A
  76. GRB 120326A: TAROT Calern observatory afterglow optical decay
  77. GRB 120326A: TAROT Calern observatory afterglow optical detection
  78. GRB 120326A: ROTSE-III Optical Limits
  79. GRB 120324A: CQUEAN rizY Observation
  80. GRB 120324A: Swift/UVOT Upper Limits
  81. GRB 120324A: TAROT La Silla observatory optical observations
  82. GRB 120324A: Liverpool Telescope optical candidate
  83. Simultaneous optical images of Swift pointing are available by GRT
  84. GRB 120320A: Zadko optical observations
  85. GRB 120229A: Magellan observations and limit on an optical afterglow
  86. GRB 120320A: Swift/UVOT Upper Limits
  87. GRB 120320A: MITSuME Okayama Optical upper limits
  88. GRB 120320A , optical observations
  89. GRB 120320A: BOOTES-4 optical upper limit
  90. GRB 120320A: Gemini-N and UKIRT observations
  91. GRB 120320A: MASTER optical observations
  92. GRB 111228A: possible detection of the SN with the TNG
  93. GRB 120312A: CrAO optical upper limit
  94. GRB 120311A: Optical follow-up
  95. GRB 120311B: Optical follow-up
  96. GRB 120311A: C88 optical limits
  97. GRB 120312A: Swift/UVOT Upper Limits
  98. GRB 120312A: MASTER-NET optical observations
  99. GRB 120312A: NOT observations
  100. GRB 120311A: VLT/X-shooter observations

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