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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"

7396 results found.

  1. GRB 040812: Second epoch CXO Observations
  2. XRF040701: Second-Epoch Chandra Observations
  3. XRF 040701, optical observations
  4. GRB 040511, very fast decay?
  5. GRB 030324: Detection and Color of Host Galaxy
  6. GRB040511: Redshift identifcation
  7. GRB 040511: Optical limit
  8. GRB040511: Candidate optical/NIR afterglow
  9. GRB 040403: Optical Observations
  10. MASTER: RXTE GRB040308 optical observation
  11. RXTE GRB040229 optical observation: no candidate
  12. GRB 040228 Optical observations
  13. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  14. GRB040106: Second Epoch Optical Observations
  15. GRB 031220: Optical observations of Chandra X-ray sources
  16. GRB031220 : Optical Observation of Lulin Observatory
  17. GRB 031111: Optical observations
  18. GRB030913: Subaru Optical Observations
  19. GRB030913, candidate afterglow observations
  20. GRB 030913, optical candidate
  21. GRB 030824: Candidate Follow-Up
  22. XRF030824: optical observations
  23. XRF030824: Palomar observations
  24. GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
  25. RAPTOR observations of GRB030823
  26. GRB 021206 Optical Observations
  27. GRB030725: Optical observations
  28. XRF030723: Re-analysis of ROTSE-III early images
  29. GRB030725, optical transient observations
  30. XRF 030723: VLT spectra
  31. RXTE PCA Observations of SGR1806-20 Region
  32. GRB 021206, Radio afterglow candidate
  33. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  34. GRB 030519B: optical observations.
  35. GRB 030528: Optical observations at RIKEN
  36. GRB030324: Further Observations of the Candidate Optical Afterglow
  37. GRB 030429: IR photometry with IRSF/SIRIUS
  38. GRB030501: TAROT candidate afterglow present in archival images
  39. GRB 030501: TAROT possible candidate counterpart
  40. GRB 030429: confirmation of afterglow candidate
  41. GRB030429, possible optical counterpart
  42. GRB 030429: ROTSE-III observations
  43. GRB 030418: Optical afterglow
  44. GRB 030418: Finder for afterglow candidate
  45. GRB 030418: Optical afterglow candidate
  46. GRB030329, UBVRI polarimetry, R-polarization
  47. GRB030324: Candidate Optical Afterglow (Erratum)
  48. GRB030324: Candidate Optical Afterglow
  49. GRB030329, new UBVRcIc field photometry
  50. GRB 030329: Additional Mt. Laguna Optical Observations
  51. GRB 030329: optical observations
  52. GRB 030329: precise position from Kyoto images
  53. GRB 030329: Optical afterglow fading
  54. GRB 030329: Optical afterglow candidate
  55. GRB 030329: OT candidate
  56. GRB 030329: Optical afterglow candidate
  57. GRB 030328: Finding chart
  58. GRB 030328: Optical afterglow candidate
  59. GRB030324 optical observation
  60. GRB030131, BVRcIc field photometry
  61. GRB030324, optical observations
  62. GRB030324, optical observations
  63. GRB030323: V, R, I photometry
  64. VLT/FORS2 spectra of GRB 030323
  65. GRB030323, ROTSE-III detection of possible optical counterpart
  66. GRB030323, optical observations
  67. GRB030323, possible optical counterpart
  68. IPN upper limit to a GRB associated with SN2003L
  69. GRB 030227 optical afterglow
  70. GRB 030227: Confirmed Optical Afterglow (S1-A)
  71. GRB 030227: fading of candidate optical afterglow 'S1-A'
  72. GRB030227 - faint tentative OT candidate
  73. GRB 030226: Optical afterglow
  74. GRB030226: Candidate optical afterglow
  75. GRB 030131: marginal optical detection
  76. GRB030131: Candidate Optical Afterglow
  77. GRB 030131, optical observations
  78. GRB030131: Kiso optical limit for corrected position
  79. GRB030131: Optical limits for corrected position
  80. GRB 030131: afterglow candidate
  81. GRB 020819: afterglow candidate
  82. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  83. GRB030115 submm upper limit
  84. GRB 030115: Further IR observations with IRSF/SIRIUS
  85. GRB 030115: Radio detection of IR candidate
  86. GRB 030115: IR observations with IRSF/SIRIUS
  87. GRB030115: R-band counterpart of IR candidate
  88. GRB030115, afterglow candidate
  89. GRB 030115, no optical candidate
  90. GRB 030115, optical candidate
  91. GRB 021112: Evidence for Another Dark Optical Afterglow
  92. XRF 020903 : HST observations
  93. GRB021204: Kiso Observations
  94. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  95. HETE 2493: Optical observations
  96. HETE 2493: Optical candidate
  97. GRB 021112: Afterglow or Variable Star?
  98. GRB 021112, Radio Observations
  99. GRB 021112: Variable Source in R-band search
  100. GRB 021113: Optical observations

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