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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"

7293 results found.

  1. GRB 040511, very fast decay?
  2. GRB 030324: Detection and Color of Host Galaxy
  3. GRB040511: Redshift identifcation
  4. GRB 040511: Optical limit
  5. GRB040511: Candidate optical/NIR afterglow
  6. GRB 040403: Optical Observations
  7. MASTER: RXTE GRB040308 optical observation
  8. RXTE GRB040229 optical observation: no candidate
  9. GRB 040228 Optical observations
  10. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  11. GRB040106: Second Epoch Optical Observations
  12. GRB 031220: Optical observations of Chandra X-ray sources
  13. GRB031220 : Optical Observation of Lulin Observatory
  14. GRB 031111: Optical observations
  15. GRB030913: Subaru Optical Observations
  16. GRB030913, candidate afterglow observations
  17. GRB 030913, optical candidate
  18. GRB 030824: Candidate Follow-Up
  19. XRF030824: optical observations
  20. XRF030824: Palomar observations
  21. GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
  22. RAPTOR observations of GRB030823
  23. GRB 021206 Optical Observations
  24. GRB030725: Optical observations
  25. XRF030723: Re-analysis of ROTSE-III early images
  26. GRB030725, optical transient observations
  27. XRF 030723: VLT spectra
  28. RXTE PCA Observations of SGR1806-20 Region
  29. GRB 021206, Radio afterglow candidate
  30. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  31. GRB 030519B: optical observations.
  32. GRB 030528: Optical observations at RIKEN
  33. GRB030324: Further Observations of the Candidate Optical Afterglow
  34. GRB 030429: IR photometry with IRSF/SIRIUS
  35. GRB030501: TAROT candidate afterglow present in archival images
  36. GRB 030501: TAROT possible candidate counterpart
  37. GRB 030429: confirmation of afterglow candidate
  38. GRB030429, possible optical counterpart
  39. GRB 030429: ROTSE-III observations
  40. GRB 030418: Optical afterglow
  41. GRB 030418: Finder for afterglow candidate
  42. GRB 030418: Optical afterglow candidate
  43. GRB030329, UBVRI polarimetry, R-polarization
  44. GRB030324: Candidate Optical Afterglow (Erratum)
  45. GRB030324: Candidate Optical Afterglow
  46. GRB030329, new UBVRcIc field photometry
  47. GRB 030329: Additional Mt. Laguna Optical Observations
  48. GRB 030329: optical observations
  49. GRB 030329: precise position from Kyoto images
  50. GRB 030329: Optical afterglow fading
  51. GRB 030329: Optical afterglow candidate
  52. GRB 030329: OT candidate
  53. GRB 030329: Optical afterglow candidate
  54. GRB 030328: Finding chart
  55. GRB 030328: Optical afterglow candidate
  56. GRB030324 optical observation
  57. GRB030131, BVRcIc field photometry
  58. GRB030324, optical observations
  59. GRB030324, optical observations
  60. GRB030323: V, R, I photometry
  61. VLT/FORS2 spectra of GRB 030323
  62. GRB030323, ROTSE-III detection of possible optical counterpart
  63. GRB030323, optical observations
  64. GRB030323, possible optical counterpart
  65. IPN upper limit to a GRB associated with SN2003L
  66. GRB 030227 optical afterglow
  67. GRB 030227: Confirmed Optical Afterglow (S1-A)
  68. GRB 030227: fading of candidate optical afterglow 'S1-A'
  69. GRB030227 - faint tentative OT candidate
  70. GRB 030226: Optical afterglow
  71. GRB030226: Candidate optical afterglow
  72. GRB 030131: marginal optical detection
  73. GRB030131: Candidate Optical Afterglow
  74. GRB 030131, optical observations
  75. GRB030131: Kiso optical limit for corrected position
  76. GRB030131: Optical limits for corrected position
  77. GRB 030131: afterglow candidate
  78. GRB 020819: afterglow candidate
  79. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  80. GRB030115 submm upper limit
  81. GRB 030115: Further IR observations with IRSF/SIRIUS
  82. GRB 030115: Radio detection of IR candidate
  83. GRB 030115: IR observations with IRSF/SIRIUS
  84. GRB030115: R-band counterpart of IR candidate
  85. GRB030115, afterglow candidate
  86. GRB 030115, no optical candidate
  87. GRB 030115, optical candidate
  88. GRB 021112: Evidence for Another Dark Optical Afterglow
  89. XRF 020903 : HST observations
  90. GRB021204: Kiso Observations
  91. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  92. HETE 2493: Optical observations
  93. HETE 2493: Optical candidate
  94. GRB 021112: Afterglow or Variable Star?
  95. GRB 021112, Radio Observations
  96. GRB 021112: Variable Source in R-band search
  97. GRB 021113: Optical observations
  98. GRB021104: Candidate present in DSS
  99. GRB021004, Optical Observations
  100. GRB 021004: radio observations

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