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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"

41067 results found.

  1. Information about where HETE will be pointing
  2. IPN triangulation of GRB030109 (annulus)
  3. IPN triangulation of GRB030105 (large error box)
  4. Coronas-F -Wind triangulation of GRB030102
  5. VLT spectroscopy of the probable host of GRB 021211
  6. GRB 021211: Probable Host and Underlying Supernova
  7. Probable GRB in INTEGRAL SPI-ACS
  8. IPN triangulation of GRB021223 (two large error boxes)
  9. GRB021211, radio observations
  10. GRB 021112: Evidence for Another Dark Optical Afterglow
  11. GRB 021219: OSN optical observations
  12. GRB021219, optical observations
  13. IPN triangulation of GRB021219
  14. GRB021219, optical observation by MASTER
  15. GRB021219 refined position with INTEGRAL
  16. GRB021219: a long GRB localized by INTEGRAL
  17. GRB021211: APO optical observations
  18. XRF 020903 : HST observations
  19. GRB 021201: Optical Observations
  20. GRB 021211, optical observations
  21. GRB 021211: CTIO observations
  22. GRB021211: Measurement of Early Time Afterglow
  23. VLT spectrum of GRB 021211
  24. GRB 021211: early break in light curve
  25. GRB021211, BVRI field photometry
  26. GRB021211: Optical observations in CrAO
  27. GRB 021211, IR observations
  28. GRB 021211, optical observations
  29. GRB 021211: Optical Observations
  30. GRB021211: Kiso Observations
  31. GRB021204: Kiso Observations
  32. GRB 021201, optical observations
  33. GRB 021211: Radio Observations
  34. GRB021211: Optical observations
  35. GRB 021201 (short/hard), NOT observations
  36. GRB 021211 Milagro GeV/TeV Observations
  37. GRB 021211, R- and I-band observations
  38. GRB021211 - Upper limits from recent and historical observations
  39. GRB021211, OT at 108 s
  40. GRB 021204: I-band Observations
  41. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  42. HETE 2493: Optical observations
  43. HETE 2493: Optical observations
  44. HETE 2493: Optical candidate
  45. GRB 021204: Optical Observations at RIKEN
  46. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  47. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  48. GRB021201, BVRcIc field photometry
  49. GRB 021201: Optical Observations
  50. GRB 021201: BOOTES simultaneous optical observations
  51. IPN triangulation of GRB021201 (short/hard burst, small error box)
  52. GRB021004, late time optical observations
  53. GRB021004 Chandra Observation
  54. IPN detection of continued SGR1900+14 activity
  55. Improved IPN error box for GRB021125
  56. IPN triangulation of GRB021125 (INTEGRAL BURST)
  57. GRB021125 : A long GRB localized by INTEGRAL
  58. IPN confirmation of the reactivation of SGR1900+14
  59. GRB021113, SPI ACS observation
  60. GRB 021112: Afterglow or Variable Star?
  61. GRB021113: optical observations at Bisei
  62. GRB 021113: Evidence for a Dark Optical Afterglow
  63. GRB021112, BVRI field photometry
  64. GRB 021112: Variable Source in R-band search
  65. GRB021112: Optical Observations
  66. GRB021113: Kiso Observations
  67. GRB 021113: Optical observations
  68. GRB 021112: RAPTOR Observations
  69. GRB 021113: Optical Observations
  70. GRB 021113: Optical Observations
  71. GRB021113 (=H2449): A Long GRB Localized by HETE
  72. GRB 021112: Optical Observations
  73. GRB 021112: R-band search
  74. IPN triangulation of GRB021108 (large error box)
  75. GRB021112 (=H2448): A Long GRB Localized by HETE
  76. GRB 021016: Optical Observations
  77. IPN triangulation of GRB021109 (annulus)
  78. GRB021104: Optical Observations
  79. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  80. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  81. Spectropolarimetry of GRB021004
  82. GRB021104: Optical observations
  83. GRB021104: optical observations
  84. GRB021104: Candidate present in DSS
  85. GRB021104: possible optical afterglow
  86. Detection of activity from SGR 1900+14 with the RXTE/PCA
  87. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  88. GRB021004, late-time optical observations
  89. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  90. IPN triangulation of GRB021025 (annulus)
  91. GRB 021004: optical observations
  92. GRB021004: Optical Observations
  93. GRB 020813; likely host galaxy.
  94. IPN triangulation of GRB021020 (smaller error box)
  95. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  96. GRB 021016, optical observations
  97. GRB 021004: VRI observations at TNG: possible break
  98. GRB021016, optical observations
  99. SGR1900+14: burst on October 10 2002
  100. GRB 021008, optical observations

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