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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"

28043 results found.

  1. GRB 030131, optical observations
  2. GRB 030131: afterglow candidate
  3. GRB 030115, late-time optical observations
  4. GRB030131: corrected INTEGRAL position
  5. GRB 020819: Host galaxy at Radio Position
  6. IPN triangulation of GRB030131
  7. GRB 030131 optical observations
  8. GRB 030131 optical observations
  9. A long GRB detected by INTEGRAL
  10. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  11. GRB 030115, simultaneous observations by BOOTES-1
  12. GRB 030115: IR observations with IRSF/SIRIUS
  13. IPN triangulation of GRB030115C (large error box)
  14. GRB030115, afterglow candidate
  15. GRB 021211: R-band observations at late-time
  16. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  17. GRB 030115 : Possible IR counterpart
  18. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  19. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  20. GRB 030115: APO Optical Observations
  21. Information about where HETE will be pointing
  22. VLT spectroscopy of the probable host of GRB 021211
  23. IPN triangulation of GRB030101 (two large error boxes)
  24. GRB 021211: Probable Host and Underlying Supernova
  25. GRB 021112: Evidence for Another Dark Optical Afterglow
  26. GRB 021219: OSN optical observations
  27. GRB021219, optical observations
  28. GRB021219, optical observation by MASTER
  29. VLT spectra of GRB 021211 revisited
  30. GRB021219: a long GRB localized by INTEGRAL
  31. GRB021211: APO optical observations
  32. XRF 020903 : HST observations
  33. GRB 021201: Optical Observations
  34. GRB 021211: CTIO observations
  35. GRB021211, BVRI field photometry
  36. GRB021211: Optical observations in CrAO
  37. GRB 021211, optical observations
  38. GRB021211: Kiso Observations
  39. GRB 021201, optical observations
  40. GRB021211: Optical observations
  41. GRB 021201 (short/hard), NOT observations
  42. SUB-MM SEARCH FOR GRB 021211
  43. Chandra observation of the IPN error box of GRB021201 (short/hard)
  44. GRB 021211, R- and I-band observations
  45. GRB021211 - Upper limits from recent and historical observations
  46. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  47. IPN triangulation of GRB021206 (small error box)
  48. IPN triangulation of GRB021205 (large error box)
  49. GRB021201, BVRcIc field photometry
  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 BURST POSITION
  57. IPN triangulation of GRB021125 (INTEGRAL BURST)
  58. GRB021125 : A long GRB localized by INTEGRAL
  59. IPN confirmation of the reactivation of SGR1900+14
  60. GRB021113, SPI ACS observation
  61. GRB 021112: Afterglow or Variable Star?
  62. GRB021113: optical observations at Bisei
  63. GRB 021113: Evidence for a Dark Optical Afterglow
  64. GRB021112, BVRI field photometry
  65. GRB 021112: Variable Source in R-band search
  66. GRB021112: Optical Observations
  67. IPN triangulation of GRB021113 (=H2449; annulus)
  68. GRB 021113: Optical observations
  69. GRB 021112: RAPTOR Observations
  70. GRB021113 (=H2449): A Long GRB Localized by HETE
  71. GRB021112 (=H2448): A Long GRB Localized by HETE
  72. GRB 021016: Optical Observations
  73. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  74. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  75. SGR1900+14 activity, November 2-4, 2002
  76. GRB021104: optical observations
  77. Detection of activity from SGR 1900+14 with the RXTE/PCA
  78. IPN triangulation of GRB021027 (single large error box)
  79. IPN triangulation of GRB021027 (two large error boxes)
  80. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  81. GRB 021004: optical observations
  82. IPN triangulation of GRB021023 (small error boc)
  83. GRB 020813; likely host galaxy.
  84. IPN triangulation of GRB021020 (smaller error box)
  85. IPN triangulation of GRB021020
  86. GRB 021008, optical observations
  87. IPN triangulation of GRB021016 (small error box)
  88. IPN triangulation of GRB021014 (large error box)
  89. IPN triangulation of GRB021013 (single error box)
  90. GRB 021004: optical spectroscopy on Oct 11
  91. IPN triangulation of GRB021013 (two small error boxes)
  92. GRB021004: High-resolution optical spectroscopy
  93. XRF 020903: flattening of the optical light curve.
  94. GRB021004, UBVRcIc field photometry update
  95. IPN triangulation of GRB021008 (single error box)
  96. GRB 021004 submm observations
  97. IPN triangulation of GRB021008 (two small error boxes)
  98. GRB021004 Chandra HETG Observations
  99. GRB 021004: Optical/NIR Observations
  100. GRB 021004: Additional V-band Polarimetric Observations

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