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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"

20536 results found.

  1. GRB 050904: Swift/UVOT observations
  2. GRB 050904: NIR object inside the XRT error box
  3. GRB 050904: SOAR YJ and PROMPT Ic Observations
  4. GRB050904: Optical Observations
  5. GRB 050904: Environmental Constraints
  6. GRB 050904: Possible High-Redshift GRB
  7. GRB 050904: SOAR/PROMPT Observations
  8. GRB050904: P60 Observations
  9. GRB 050824: MDM Observations
  10. GRB 050827 : OSN 1.5m optical observations
  11. GRB 050827: P200 NIR Observations
  12. GRB 050826 : Lulin R band observation
  13. GRB050820A: RTT150 optical observations
  14. GRB050827: RTT150 optical observations
  15. Subaru Observations of GRB050724
  16. GRB 050826: Optical Candidate
  17. GRB050826: Swift-BAT detection of a long burst
  18. GRB050824: MASTER final analysis of the OT observations
  19. Possible GRB050825:MASTER optical observations
  20. GRB050824: CORRECTION to UVOT observing times
  21. GRB050824: Swift/UVOT detection of fading afterglow
  22. GRB050824, I-band imaging
  23. GRB050824: Radio Observations
  24. GRB 050824 optical candidate
  25. GRB050820A: RTT150 optical observations
  26. GRB050820a: PROMPT RcIc Observations
  27. VLT/UVES spectroscopy of GRB050820
  28. GRB 050820A BAT observations of second, larger episode of emission
  29. GRB050813: Maidanak I-band observations
  30. GRB050820A: RTT150 optical observations
  31. GRB 050822: ROTSE-III Prompt Optical Limits
  32. GRB050820A: Radio Observation
  33. GRB 050820a: NIR Observations by WIRO
  34. GRB 050820B: Swift XRT position
  35. Swift/UVOT photometry of GRB050820
  36. GRB050820: refined XRT analysis
  37. GRB 050820: P60 Temporal Decay Index
  38. GRB 050820: High Resolution Spectroscopy from Keck
  39. GRB050819: refined XRT analysis
  40. GRB050819: RTT150 optical observations
  41. GRB 050820: Swift detection of a GRB
  42. GRB 050817: Optical observations
  43. GRB 050815: Radio Observation
  44. GRB050814: Radio Observation
  45. GRB050817: Negative Optical Observations
  46. GRB050817: Swift-BAT Detection of a burst
  47. GRB050815: Optical afterglow detection by Swift UVOT
  48. GRB 050813: Radio Observations
  49. GRB 050730: Third Epoch WSRT Radio Observations
  50. GRB 050813: Gemini Spectra Revisited
  51. GRB050814: P60 Optical Afterglow Candidate
  52. GRB 050813: Non-fading of afterglow candidate
  53. GRB050813: Gemini Imaging
  54. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  55. GRB 050813: Magellan detection of a high redshift galaxy cluster
  56. GRB050813: RTT150 optical observations
  57. GRB 050813: I-band observations
  58. GRB050813, SDSS pre-burst observations
  59. GRB 050813: Photometry of object in XRT error circle
  60. RBO GRB 050714A and GRB 050716 observations
  61. GRB050813 (Swift 150139): P60 Observations
  62. GRB050803: CrAO optical observations, no OT candidate
  63. GRB 050730: WSRT Radio Observations
  64. GRB 050803: PROMPT BVRcIc Observations
  65. GRB 050807: ROTSE-III Optical Limits
  66. GRB 050730, optical observation
  67. GRB050805a : Null detection report
  68. GRB050730, optical observations
  69. GRB050803, optical observations
  70. Swift-BAT trigger 149118 is very likely not a GRB
  71. GRB050805b: MASTER optical observations
  72. GRB050802: TNG optical observations
  73. GRB050803: Radio Observation
  74. GRB 050803: RTT150 optical observations
  75. GRB050730: Radio Detection
  76. GRB050803: CrAO optical observations, possible OT candidate
  77. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  78. GRB 050803: Keck Observations
  79. GRB 050802.422: Fading of the afterglow and detection of the host
  80. GRB 050803, optical observations
  81. GRB 050803: Magellan Observations
  82. GRB 050803: TAROT optical limits
  83. GRB050803: MASTER optical observations
  84. GRB050802: Tentative absorption redshift
  85. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  86. GRB 050802: Swift/UVOT optical and UV detections
  87. GRB050802: CrAO optical observations
  88. GRB 050730: OHP optical observations
  89. GRB 050802: Swift/UVOT observations
  90. GRB 050802: Swift Gamma-ray Burst
  91. GRB 050730: Preliminary Analysis of MIKE Spectrum
  92. GRB 050801, SMARTS optical/IR afterglow observations
  93. GRB 050801, afterglow observations
  94. GRB 050730, corrected photometry and break?
  95. GRB050801: Swift-BAT detection of a burst
  96. GRB 050801: ROTSE-III Detection of Possible Counterpart
  97. GRB 050730: XRT refined analysis
  98. GRB 050730: early TAROT optical observations
  99. GRB 050726: PROMPT Rc Observations
  100. GRB 050730: RTT150 optical observations

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