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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 120311B: C88 optical limits
  2. GRB 120311B: Swift/UVOT Upper Limits
  3. GRB 120311B: MITSuME Okayama Optical upper limits
  4. GRB 120311A: Swift/UVOT Upper Limits
  5. GRB 120311A: CAHA 1.23m I-band early observations
  6. GRB 120311A: Liverpool Telescope optical candidate
  7. GRB 120308A : LOAO optical observation
  8. GRB 120308A: RTT150 optical observations
  9. GRB 120302A: RTT150 optical observations
  10. GRB 120308A: 1.23m CAHA I-band observations
  11. GRB 120308A: Further PAIRITEL NIR Observations
  12. GRB120308A: MITSuME Ishigakijima Optical Upper Limits
  13. GRB 120308A: Swift/UVOT Detection
  14. GRB 120308A: IAC80 I-band observations
  15. GRB 120308A: confirmation of the optical afterglow
  16. GRB 120308A: Liverpool Telescope optical afterglow candidate
  17. GRB 120305A: D50 optical limits
  18. GRB 120302A: Swift-BAT refined position and a possible XRT and UVOT counterpart
  19. GRB 120305A: Swift/UVOT Upper Limits
  20. GRB 120305A - Liverpool Telescope Observations
  21. GRB 120305A: MASTER-NET early optical observations
  22. GRB 120302A: GROND detection of an afterglow candidate
  23. GRB 120227A: RAPTOR Limit During the Gamma-Ray Emitting Interval
  24. GRB 120224A: optical observation in Mondy observatory
  25. GRB 120224A: Swift/UVOT Upper Limits
  26. GRB 120224A: FTN optical observations
  27. GRB 1202019A: optical observation in Mondy observatory
  28. GRB 120219A: MASTER prompt and early optical limit and OT discussion
  29. GRB 120219A: 1.23m CAHA optical observations
  30. GCN 12974 : Errata in the Subject
  31. GRB 120219A, optical observations
  32. GRB 120215A: MITSuME Akeno Optical upper limits
  33. GRB 120219A: Swift/UVOT Upper Limits
  34. GRB 120219A: MITSuME Okayama Optical upper limits
  35. GRB120219A: TNT optical afterglow candidates
  36. GRB 120219A: MASTER-NET prompt and early optical observations
  37. GRB 120215A: Swift/UVOT Upper Limits
  38. GRB 120215A: MITSuME Okayama Optical upper limits
  39. Skynet/PROMPT observations of GRB120215A
  40. GRB 120211A : LOAO optical observations
  41. GRB 120213A: Swift/UVOT Upper Limits
  42. GRB 120212A: GMG optical observation
  43. GRB 120212A: MITSuME Ishigakijima Optical Observation
  44. GRB 120213A: MASTER-NET early optical observations
  45. GRB 120212A: NOT optical observation
  46. GRB 120212A: Kanata/HOWPol optical observation
  47. GRB 120211A: MITSuME Okayama and Ishigakijima Optical upper limits
  48. GRB 120211A, optical observations
  49. GRB 120211A: Swift/UVOT Upper Limits
  50. GRB 120211A: MASTER early optical observations
  51. GRB 120211A - Faulkes Telescope South Observations
  52. GRB 120202A: MASTER early optical observations
  53. GRB 120202A: D50 optical limits
  54. GRB 120202A: GROND observations
  55. GRB 120202A: Swift/XRT and UVOT observations
  56. GRB 120202A: TAROT Calern observatory optical observations
  57. GRB 111228A: Possible host detected by Swift/UVOT
  58. GRB 120129A: MASTER optical observations
  59. GRB 120127A / P48 Imaging
  60. GRB 120127A: MASTER optical observations
  61. GRB 120118B: optical upper limit
  62. GRB 120116A: optical upper limit
  63. GRB 120119A : LOAO Optical Observations
  64. GRB 120119A: EVLA observations
  65. GRB 120119A: GRT detection of early afterglow
  66. GRB 111225A: optical observations
  67. GRB 120119A: optical upper limit
  68. GRB 120121A: Swift/UVOT Upper Limits
  69. GRB 120121A: ISON-NM optical observations
  70. GRB 120119A: TAROT La Silla observatory optical observations
  71. GRB120119A: REM NIR observations
  72. GRB 120119A: optical observations
  73. GRB 120118B: RTT150 optical observations
  74. GRB 120119A: SMARTS optical/IR afterglow observations
  75. GRB 120119A: optical observations
  76. GRB 120118B : Lulin Optical limit
  77. GRB 120119A: MMT redshift confirmation
  78. GRB 120119A: Gemini-S redshift
  79. GRB 120119A: PROMPT optical observation of early afterglow
  80. GRB 120119A: GROND Detection of the Optical/NIR Afterglow
  81. GRB 120118B: Swift/UVOT Upper Limits
  82. GRB 120119A: PAIRITEL NIR Detection
  83. GRB 120119A: Swift detection of a burst with an optical counterpart
  84. GRB 120118B: NOT observations
  85. XRF 120118A: early optical limit by "Pi of the Sky"
  86. GRB 120118B: MASTER optical observations
  87. XRF 120118A: Optical candidate
  88. GRB 120116A: Swift/UVOT Upper Limits
  89. AXP 4U 1042+61: Mondy optical observations
  90. GRB 120116A: Mondy optical observations
  91. GRB 120116A: Gemini optical/IR candidate
  92. GRB 120116A: WHT optical observations
  93. GRB 120116A: Optical observations at Crni Vrh
  94. GRB 120116A: NOT observations
  95. GRB 120116A: Bassano Bresciano Observatory optical observations
  96. GRB 120116A: MASTER Early optical limit
  97. GRB 111228A: optical observations
  98. GRB 120106A: optical upper limit
  99. GRB 120106A: MITSuME Okayama Optical Observation (update)
  100. GRB 120106A: Swift/UVOT Upper Limits

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