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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"

25727 results found.

  1. GRB 030115 : Possible IR counterpart
  2. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  3. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  4. GRB 030115: APO Optical Observations
  5. Information about where HETE will be pointing
  6. VLT spectroscopy of the probable host of GRB 021211
  7. IPN triangulation of GRB030101 (two large error boxes)
  8. GRB 021211: Probable Host and Underlying Supernova
  9. GRB 021112: Evidence for Another Dark Optical Afterglow
  10. GRB 021219: OSN optical observations
  11. GRB021219, optical observations
  12. GRB021219, optical observation by MASTER
  13. VLT spectra of GRB 021211 revisited
  14. GRB021219: a long GRB localized by INTEGRAL
  15. GRB021211: APO optical observations
  16. XRF 020903 : HST observations
  17. GRB 021201: Optical Observations
  18. GRB 021211: CTIO observations
  19. GRB021211, BVRI field photometry
  20. GRB021211: Optical observations in CrAO
  21. GRB 021211, optical observations
  22. GRB021211: Kiso Observations
  23. GRB 021201, optical observations
  24. GRB021211: Optical observations
  25. GRB 021201 (short/hard), NOT observations
  26. SUB-MM SEARCH FOR GRB 021211
  27. Chandra observation of the IPN error box of GRB021201 (short/hard)
  28. GRB 021211, R- and I-band observations
  29. GRB021211 - Upper limits from recent and historical observations
  30. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  31. IPN triangulation of GRB021206 (small error box)
  32. IPN triangulation of GRB021205 (large error box)
  33. GRB021201, BVRcIc field photometry
  34. GRB 021201: BOOTES simultaneous optical observations
  35. IPN triangulation of GRB021201 (short/hard burst, small error box)
  36. GRB021004, late time optical observations
  37. GRB021004 Chandra Observation
  38. IPN detection of continued SGR1900+14 activity
  39. Improved IPN error box for GRB021125
  40. IPN BURST POSITION
  41. IPN triangulation of GRB021125 (INTEGRAL BURST)
  42. GRB021125 : A long GRB localized by INTEGRAL
  43. IPN confirmation of the reactivation of SGR1900+14
  44. GRB021113, SPI ACS observation
  45. GRB 021112: Afterglow or Variable Star?
  46. GRB021113: optical observations at Bisei
  47. GRB 021113: Evidence for a Dark Optical Afterglow
  48. GRB021112, BVRI field photometry
  49. GRB 021112: Variable Source in R-band search
  50. GRB021112: Optical Observations
  51. IPN triangulation of GRB021113 (=H2449; annulus)
  52. GRB 021113: Optical observations
  53. GRB 021112: RAPTOR Observations
  54. GRB021113 (=H2449): A Long GRB Localized by HETE
  55. GRB021112 (=H2448): A Long GRB Localized by HETE
  56. GRB 021016: Optical Observations
  57. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  58. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  59. SGR1900+14 activity, November 2-4, 2002
  60. GRB021104: optical observations
  61. Detection of activity from SGR 1900+14 with the RXTE/PCA
  62. IPN triangulation of GRB021027 (single large error box)
  63. IPN triangulation of GRB021027 (two large error boxes)
  64. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  65. GRB 021004: optical observations
  66. IPN triangulation of GRB021023 (small error boc)
  67. GRB 020813; likely host galaxy.
  68. IPN triangulation of GRB021020 (smaller error box)
  69. IPN triangulation of GRB021020
  70. GRB 021008, optical observations
  71. IPN triangulation of GRB021016 (small error box)
  72. IPN triangulation of GRB021014 (large error box)
  73. IPN triangulation of GRB021013 (single error box)
  74. GRB 021004: optical spectroscopy on Oct 11
  75. IPN triangulation of GRB021013 (two small error boxes)
  76. GRB021004: High-resolution optical spectroscopy
  77. XRF 020903: flattening of the optical light curve.
  78. GRB021004, UBVRcIc field photometry update
  79. IPN triangulation of GRB021008 (single error box)
  80. GRB 021004 submm observations
  81. IPN triangulation of GRB021008 (two small error boxes)
  82. GRB021004 Chandra HETG Observations
  83. GRB 021004: Optical/NIR Observations
  84. GRB 021004: Additional V-band Polarimetric Observations
  85. GRB021004: optical observation
  86. GRB 021004: Host Galaxy Star Formation Rate
  87. GRB 021004 submm observations
  88. GRB 021004: WC wind?
  89. GRB021004: NIR and Optical observations
  90. GRB 021004: Optical observations, AUDE network
  91. GRB 021004 - VLA Radio Observations
  92. GRB 021004 - Unusual Radio-to-Submm Spectrum
  93. GRB 021004: optical spectroscopy
  94. IPN triangulation of GRB021007 (annulus)
  95. GRB021004: optical observations and predicted break time
  96. GRB021004: BVRc photometry
  97. GRB021004 radio observation
  98. HETE fluences for GRB021004
  99. GRB 021004: Optical Photometry at 2.5 Days
  100. GRB 021004: polarimetric observations

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