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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"

27553 results found.

  1. GRB 030227: Confirmed Optical Afterglow (S1-A)
  2. GRB 030226: R band polarimetric observations
  3. GRB 030227: fading of candidate optical afterglow 'S1-A'
  4. GRB030227:Optical observations
  5. GRB 030227, possible optical counterpart of XMM-Newton source
  6. GRB 030226, optical observations
  7. GRB 030226, optical light curve
  8. GRB 030226 spectroscopy
  9. GRB030227 localized by INTEGRAL
  10. Possible break in the GRB 030226 light curve
  11. GRB 030226 : Predicted light curve
  12. GRB030226: optical observation
  13. GRB 030226: Confirmed decay index
  14. GRB030226: ESI spectroscopy
  15. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  16. Two absorption systems in GRB 030226
  17. GRB 030226, optical observations
  18. GRB030226: optical observations and refined redshift
  19. GRB030226: Optical decay index
  20. GRB 030226 Optical Spectra and R,I,z' Imaging
  21. GRB 030226: Optical afterglow
  22. GRB030226: Candidate optical afterglow
  23. GRB 030217: Optical Observations at 4, 5, and 6 Days
  24. GRB030115, WSRT radio observations - correction to GCN 1864
  25. GRB 030131: marginal optical detection
  26. GRB030115, WSRT radio observations
  27. GRB030204 field photometry
  28. GRB020819: Kiso R and I band observations
  29. GRB030131: Candidate Optical Afterglow
  30. GRB 030131, optical observations
  31. GRB030131: Optical limits for corrected position
  32. GRB 030131: afterglow candidate
  33. GRB 020819: afterglow candidate
  34. A long GRB detected by INTEGRAL
  35. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  36. GRB030115 submm upper limit
  37. GRB 030115: Further IR observations with IRSF/SIRIUS
  38. GRB 030115: Radio detection of IR candidate
  39. GRB 030115: IR observations with IRSF/SIRIUS
  40. GRB030115: R-band counterpart of IR candidate
  41. GRB030115, afterglow candidate
  42. GRB 021211: R-band observations at late-time
  43. GRB030115: TAROT optical observations
  44. GRB 021211: VLT spectrum
  45. GRB 030115, optical candidate
  46. GRB 021211: Probable Host and Underlying Supernova
  47. GRB021211, radio observations
  48. GRB 021112: Evidence for Another Dark Optical Afterglow
  49. VLT spectra of GRB 021211 revisited
  50. GRB021219: a long GRB localized by INTEGRAL
  51. GRB021211: APO optical observations
  52. IPN detection of continued activity from SGR1806-20
  53. GRB 021211, optical observations
  54. GRB 021211: CTIO observations
  55. GRB021211: Measurement of Early Time Afterglow
  56. VLT spectrum of GRB 021211
  57. GRB 021211: early break in light curve
  58. GRB021211: Optical observations in CrAO
  59. GRB 021211, IR observations
  60. GRB 021211, optical observations
  61. GRB021211: Kiso Observations
  62. GRB021204: Kiso Observations
  63. GRB021211: Optical observations
  64. GRB 021211, R- and I-band observations
  65. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  66. HETE 2493: Optical observations
  67. HETE 2493: Optical observations
  68. IPN detection of renewed activity from SGR1806-20
  69. GRB021201, BVRcIc field photometry
  70. IPN detection of continued SGR1900+14 activity
  71. GRB021125 : A long GRB localized by INTEGRAL
  72. IPN detection of possible reactivation of SGR1900+14
  73. GRB 021112: Afterglow or Variable Star?
  74. GRB 021113: Evidence for a Dark Optical Afterglow
  75. GRB021112, BVRI field photometry
  76. GRB 021113: Optical observations
  77. GRB021004: Near infrared spectroscopy
  78. GRB021104: optical observations
  79. GRB021104: Candidate present in DSS
  80. GRB021104: possible optical afterglow
  81. Detection of activity from SGR 1900+14 with the RXTE/PCA
  82. GRB021004, late-time optical observations
  83. GRB021004: Optical Observations
  84. GRB 020813; likely host galaxy.
  85. GRB 021016, optical observations
  86. GRB 021008, optical observations
  87. GRB021004: Optical Observations
  88. GRB 021004: optical spectroscopy on Oct 11
  89. GRB021004: High-resolution optical spectroscopy
  90. GRB021004, UBVRcIc field photometry update
  91. GRB021004: Optical Observations
  92. GRB021004 Chandra HETG Observations
  93. GRB021004: optical observation
  94. GRB 021004: WC wind?
  95. GRB 021004: Optical observations, AUDE network
  96. GRB 021004 - VLA Radio Observations
  97. GRB 021004 - Unusual Radio-to-Submm Spectrum
  98. GRB 021004: optical spectroscopy
  99. GRB021004: optical observations and predicted break time
  100. GRB021004: BVRc photometry

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