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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"

20955 results found.

  1. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  2. GRB 050904: More SOAR
  3. GRB 050904: Swift/UVOT observations
  4. GRB 050904: NIR object inside the XRT error box
  5. GRB 050904: SOAR YJ and PROMPT Ic Observations
  6. GRB 050904: BAT refined analysis of partial data set
  7. GRB050904: Optical Observations
  8. GRB 050904: Environmental Constraints
  9. GRB 050904: Possible High-Redshift GRB
  10. GRB 050904: SOAR/PROMPT Observations
  11. GRB050904: P60 Observations
  12. GRB 050824: MDM Observations
  13. GRB 050827 : OSN 1.5m optical observations
  14. GRB 050827: P200 NIR Observations
  15. GRB 050826 : Lulin R band observation
  16. GRB050820A: RTT150 optical observations
  17. GRB050827: RTT150 optical observations
  18. Subaru Observations of GRB050724
  19. GRB 050826: Optical Candidate
  20. GRB050826: Swift-BAT detection of a long burst
  21. GRB050824: MASTER final analysis of the OT observations
  22. Possible GRB050825:MASTER optical observations
  23. GRB050824: CORRECTION to UVOT observing times
  24. GRB050824: Swift/UVOT detection of fading afterglow
  25. GRB050824, I-band imaging
  26. GRB050824: Radio Observations
  27. GRB050824: MASTER:OT decay
  28. GRB 050824 optical candidate
  29. GRB050820A: RTT150 optical observations
  30. GRB050820a: PROMPT RcIc Observations
  31. VLT/UVES spectroscopy of GRB050820
  32. GRB 050820A BAT observations of second, larger episode of emission
  33. GRB050813: Maidanak I-band observations
  34. GRB050820A: RTT150 optical observations
  35. GRB 050822: ROTSE-III Prompt Optical Limits
  36. GRB050820A: Radio Observation
  37. GRB 050820a: NIR Observations by WIRO
  38. GRB 050820B: Swift XRT position
  39. Swift/UVOT photometry of GRB050820
  40. GRB050820: refined XRT analysis
  41. GRB 050820: P60 Temporal Decay Index
  42. GRB 050820: High Resolution Spectroscopy from Keck
  43. GRB050819: refined XRT analysis
  44. GRB050819: RTT150 optical observations
  45. GRB 050820: Swift detection of a GRB
  46. GRB 050817: Optical observations
  47. GRB 050815: Radio Observation
  48. GRB050814: Radio Observation
  49. GRB050817: Negative Optical Observations
  50. GRB050817: Swift-BAT Detection of a burst
  51. GRB 050814: continued fading
  52. GRB050815: Optical afterglow detection by Swift UVOT
  53. GRB 050813: Radio Observations
  54. GRB 050730: Third Epoch WSRT Radio Observations
  55. GRB050814: P60 Optical Afterglow Candidate
  56. GRB 050813: Non-fading of afterglow candidate
  57. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  58. GRB 050813: Magellan detection of a high redshift galaxy cluster
  59. GRB050813: RTT150 optical observations
  60. GRB 050813: I-band observations
  61. GRB050813, SDSS pre-burst observations
  62. RBO GRB 050714A and GRB 050716 observations
  63. GRB050813 (Swift 150139): P60 Observations
  64. GRB050803: CrAO optical observations, no OT candidate
  65. GRB 050730: WSRT Radio Observations
  66. GRB 050803: PROMPT BVRcIc Observations
  67. GRB 050807: ROTSE-III Optical Limits
  68. GRB 050730, optical observation
  69. GRB050805a : Null detection report
  70. GRB050730, optical observations
  71. GRB050803, optical observations
  72. Swift-BAT trigger 149118 is very likely not a GRB
  73. GRB050805b: MASTER optical observations
  74. GRB050802: TNG optical observations
  75. GRB050803: Radio Observation
  76. GRB 050803: RTT150 optical observations
  77. GRB050730: Radio Detection
  78. GRB050803: CrAO optical observations, possible OT candidate
  79. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  80. GRB 050803: Keck Observations
  81. GRB 050803, optical observations
  82. GRB 050803: Magellan Observations
  83. GRB 050803: early Swift XRT analysis results
  84. GRB 050803: TAROT optical limits
  85. GRB050803: MASTER optical observations
  86. GRB050802: Tentative absorption redshift
  87. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  88. GRB 050802: Swift/UVOT optical and UV detections
  89. GRB050802: CrAO optical observations
  90. GRB 050730: OHP optical observations
  91. GRB 050802: Swift/UVOT observations
  92. GRB 050802: Swift Gamma-ray Burst
  93. GRB 050801, SMARTS optical/IR afterglow observations
  94. GRB 050801, afterglow observations
  95. GRB 050730, corrected photometry and break?
  96. GRB050801: Swift-BAT detection of a burst
  97. GRB 050801: ROTSE-III Detection of Possible Counterpart
  98. GRB 050730: XRT refined analysis
  99. GRB 050730: early TAROT optical observations
  100. GRB 050726: PROMPT Rc Observations

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