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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"

12026 results found.

  1. Swift/UVOT observations of GRB130505A
  2. GRB 130505A: MAXI/GSC detection
  3. GRB 130504A: MITSuME Okayama upper limits
  4. GRB 130504A: Bassano Bresciano Observatory optical upper limit
  5. GRB 130504A: Swift/UVOT Upper Limits
  6. Trigger 555096: Swift detection of a possible burst
  7. GRB130502A: MASTER-Net optical observations
  8. GRB 130502B: Swift/UVOT Upper Limits
  9. GRB 130502A: Swift/UVOT Upper Limits
  10. GRB 130502B: P60 Observations
  11. GRB 130502A: RATIR Optical and NIR Observations
  12. GRB 130427A: MITSuME Ishigakijima Optical Observation after 5 days
  13. GRB 130502A: Swift detection of a burst
  14. GRB 130425: MASTER-Net optical observations
  15. GRB 130427B: MITSuME Ishigakijima upper limits
  16. GRB 130427B: RATIR Optical and NIR Observations
  17. GRB 130427B: MITSuME Okayama upper limits
  18. GRB 130427A: MAXI/GSC detection
  19. Trigger 554491: Swift detection of a spike possibly from Sgr A*
  20. GRB 130420A: Continued RATIR Optical and NIR Observations
  21. GRB 130420A: Continued RATIR Optical and NIR Observations
  22. GRB 130418A: Continued RATIR Optical and NIR Observations
  23. Swift Trigger 554135 is probably not a GRB or transient
  24. GRB 130420B: RATIR Optical and NIR Observations
  25. GRB 130420B: Weihai optical upper limit
  26. GRB 130420B: Swift/UVOT Upper Limits
  27. GRB 130420A: Swift/UVOT Detection
  28. GRB130420B: GMG optical upper limit
  29. GRB130420A : Xinglong TNT optical upper limit
  30. GRB 130420B: MASTER-Net optical observations
  31. GRB 130420B: Swift detection of a burst
  32. GRB 130419B (Swift trigger Trigger 553930): MASTER-Net optical observations
  33. GRB 130407A: Swift-XRT observations
  34. GRB130408A: Swift/UVOT followup observations
  35. GRB 130407A: MAXI/GSC detection
  36. Swift detection of IGR J18245-2452
  37. GRB 130306A: Confirmation of the X-ray Afterglow
  38. Swift Trigger 552142: a possible GRB
  39. GRB 130327A: Gemini Observations
  40. GRB 130327A: Swift/UVOT Upper Limits
  41. GRB 130327A: ISON-NM optical upper limit
  42. GRB 130327A: RATIR Optical and NIR Observations
  43. GRB 130305A: optical upper limit in Mondy observatory
  44. GRB 130315A: Swift/UVOT Upper Limits
  45. GRB 130313A: optical upper limit in CrAO
  46. GRB 130313A: optical upper limit in Mondy observatory
  47. GRB 130315A: SALT optical observations
  48. GRB 130313A: 5.8 GHz VLA upper limit
  49. Swift XRT observations of GRB 130310A
  50. GRB 130313A: Swift/UVOT Upper Limits
  51. GRB 130305A: PTF P48 optical upper limits
  52. GRB 130315A: Swift detection of a burst
  53. GRB 130305A: TLS Tautenburg observations
  54. GRB 130313A: RATIR Optical and NIR Observations
  55. GRB 130313A: Fading X-ray Afterglow
  56. GRB 130313A: NOT optical upper limit
  57. GRB 130313A: Weihai optical upper limit
  58. GRB 130313A: MASTER-Net optical observations
  59. GRB 130313A: Swift detection of a short burst
  60. GRB 130306A: Swift Detection of a Possible Afterglow
  61. GRB 130306A: MITSuME Ishigakijima upper limits
  62. GRB 130305A: Gemini-North upper limit
  63. GRB 130306A: MASTER-Net pre-Swift alert observation
  64. GRB 130305A: Swift/UVOT Upper Limit
  65. GRB 130305A: RATIR Observations
  66. GRB 121128A: optical upper limit in Maidanak observatory
  67. GRB 130216A: Swift/UVOT Upper Limit
  68. SGR 1806-20 outburst (trigger 549841), Swift-BAT refined analysis
  69. GRB 130216A: possible radio counterpart is steady field source
  70. GRB 130216A: Swift/XRT observations
  71. GRB 130216B: Swift/XRT observations
  72. GRB 130216B: MASTER-Net early observation
  73. GRB 130216A: MASTER-Net early observations
  74. GRB 130216A: MITSuME Ishigakijima upper limits
  75. GRB 130215A: MITSuME Okayama Optical Observation
  76. Swift GRB130206A: late XRT observations.
  77. GRB 130131B: CTIO 0.9-m optical upper-limits
  78. GRB 130211A: Swift/UVOT Upper Limits
  79. GRB 130211A: Swift detection of a burst
  80. GRB 130131A: MITSuME Akeno Optical upper limits
  81. GRB 130131B: MITSuME Akeno Optical upper limits
  82. GRB 130122A: PTF P48 optical upper limits
  83. GRB 130206A: GROND Observations
  84. GRB 130206A: Fermi LAT Observations
  85. GRB 130206A: XRT and UVOT follow-up observations.
  86. GRB 130131B: optical upper limit in Mondy observatory
  87. GRB 130131A: Swift/UVOT Upper Limits
  88. GRB 130131B: RATIR Upper Limits
  89. GRB 130131A: RATIR optical and infrared upper limits
  90. GRB 130131B: GROND Upper limits
  91. GRB 130131B: Swift/UVOT Upper Limits
  92. GRB 130131B: MITSuME Okayama optical upper limits
  93. GRB 130131A: MITSuME Okayama optical upper limits
  94. GRB 130131B: Swift detection of a burst
  95. GRB 130131A: Swift detection of a burst
  96. Swift Trigger 547142: MAXI/GSC upper limit
  97. GRB 130122A: Swift/UVOT Detection
  98. GRB 130122A: RATIR Detection
  99. GRB 130122A: Xinglong optical upper limit
  100. GRB 130102B: MASTER synchronous observations

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