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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"

20561 results found.

  1. GRB 030324 optical observations
  2. GRB 030320: Optical Observations
  3. GRB 030324, optical observations
  4. GRB030226, addendum to GCN 1892
  5. GRB 030226 Optical observations
  6. GRB030226: Optical observations at Asiago
  7. GRB 030226: Optical observations
  8. GRB 030227: Optical observations
  9. GRB030226, BVRc observations
  10. GRB 030226, further optical/NIR imaging
  11. GRB030227, optical observations
  12. GRB 030226: Ic Observations
  13. GRB 030228, optical observations
  14. GRB 030226: Steep Decline
  15. GRB 030226: R band polarimetric observations
  16. GRB 030226: Optical observations
  17. GRB030227:Optical observations
  18. GRB 20030226: Upper limits from recent and historical observations
  19. GRB 030227, possible optical counterpart of XMM-Newton source
  20. GRB 030226, optical observations
  21. GRB030227: Kiso optical observations
  22. GRB 030226, optical light curve
  23. GRB030226: optical observation
  24. GRB030226: ESI spectroscopy
  25. GRB 030226 simultaneous optical observations
  26. GRB 030226, optical observations
  27. GRB030226: optical observations and refined redshift
  28. GRB030226: Optical decay index
  29. GRB 030226, optical observations
  30. GRB030226: Candidate optical afterglow
  31. GRB 030217: Optical Observations at 4, 5, and 6 Days
  32. GRB030217: optical observations
  33. GRB030115, WSRT radio observations - correction to GCN 1864
  34. GRB 030131: marginal optical detection
  35. GRB030115, WSRT radio observations
  36. GRB 030204: Optical Observations
  37. GRB020819: Kiso R and I band observations
  38. GRB030131: Candidate Optical Afterglow
  39. GRB 030115: Optical Observations
  40. GRB 030204, optical observations
  41. GRB 030131, optical observations
  42. GRB030131: Optical limits for corrected position
  43. GRB 030115, late-time optical observations
  44. GRB030131: Kiso Observations
  45. GRB 020819: Host galaxy at Radio Position
  46. GRB030131: Optical limit
  47. GRB 030131 optical observations
  48. GRB 030131 optical observations
  49. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  50. Type Ic SN2003L (SN/GRB?) Radio Observations
  51. GRB030115 submm upper limit
  52. GRB 030115: Further IR observations with IRSF/SIRIUS
  53. GRB 030115: Radio detection of IR candidate
  54. GRB 030115, simultaneous observations by BOOTES-1
  55. GRB 030115: IR observations with IRSF/SIRIUS
  56. GRB030115: R-band counterpart of IR candidate
  57. GRB 021211: R-band observations at late-time
  58. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  59. GRB 030115 : Possible IR counterpart
  60. GRB 030115: Radio Observations
  61. GRB030115: R-band observations at Asiago
  62. GRB030115: TAROT optical observations
  63. GRB 021211: VLT spectrum
  64. GRB 030115: APO Optical Observations
  65. GRB 030115, no optical candidate
  66. GRB 030115, optical observations
  67. GRB 030115, optical candidate
  68. Information about where HETE will be pointing
  69. VLT spectroscopy of the probable host of GRB 021211
  70. GRB 021211: Probable Host and Underlying Supernova
  71. GRB021211, radio observations
  72. GRB 021219: OSN optical observations
  73. GRB021219: Radio Observations
  74. GRB021219, optical observations
  75. IPN triangulation of GRB021219
  76. VLT spectra of GRB 021211 revisited
  77. GRB021211: APO optical observations
  78. XRF 020903 : HST observations
  79. GRB 021201: Optical Observations
  80. GRB 021211, optical observations
  81. GRB 021211: CTIO observations
  82. VLT spectrum of GRB 021211
  83. GRB 021211: early break in light curve
  84. GRB021211: Optical observations in CrAO
  85. GRB 021211, IR observations
  86. GRB 021211, optical observations
  87. GRB 021211: Optical Observations
  88. GRB021211: Kiso Observations
  89. GRB021204: Kiso Observations
  90. GRB 021201, optical observations
  91. GRB 021211: Radio Observations
  92. GRB021211: Optical observations
  93. GRB 021201 (short/hard), NOT observations
  94. SUB-MM SEARCH FOR GRB 021211
  95. GRB 021211 Milagro GeV/TeV Observations
  96. GRB 021211, R- and I-band observations
  97. GRB021211 - Upper limits from recent and historical observations
  98. GRB021211, OT at 108 s
  99. GRB 021204: I-band Observations
  100. HETE 2493: Optical observations

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