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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"

27407 results found.

  1. GRB 021211, optical observations
  2. GRB021211: Kiso Observations
  3. GRB 021201, optical observations
  4. GRB021211: Optical observations
  5. GRB 021201 (short/hard), NOT observations
  6. SUB-MM SEARCH FOR GRB 021211
  7. Chandra observation of the IPN error box of GRB021201 (short/hard)
  8. GRB 021211, R- and I-band observations
  9. GRB021211 - Upper limits from recent and historical observations
  10. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  11. IPN triangulation of GRB021206 (small error box)
  12. IPN triangulation of GRB021205 (large error box)
  13. GRB021201, BVRcIc field photometry
  14. GRB 021201: BOOTES simultaneous optical observations
  15. IPN triangulation of GRB021201 (short/hard burst, small error box)
  16. GRB021004, late time optical observations
  17. GRB021004 Chandra Observation
  18. IPN detection of continued SGR1900+14 activity
  19. Improved IPN error box for GRB021125
  20. IPN BURST POSITION
  21. IPN triangulation of GRB021125 (INTEGRAL BURST)
  22. GRB021125 : A long GRB localized by INTEGRAL
  23. IPN confirmation of the reactivation of SGR1900+14
  24. GRB021113, SPI ACS observation
  25. GRB 021112: Afterglow or Variable Star?
  26. GRB021113: optical observations at Bisei
  27. GRB 021113: Evidence for a Dark Optical Afterglow
  28. GRB021112, BVRI field photometry
  29. GRB 021112: Variable Source in R-band search
  30. GRB021112: Optical Observations
  31. IPN triangulation of GRB021113 (=H2449; annulus)
  32. GRB 021113: Optical observations
  33. GRB 021112: RAPTOR Observations
  34. GRB021113 (=H2449): A Long GRB Localized by HETE
  35. GRB021112 (=H2448): A Long GRB Localized by HETE
  36. GRB 021016: Optical Observations
  37. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  38. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  39. SGR1900+14 activity, November 2-4, 2002
  40. GRB021104: optical observations
  41. Detection of activity from SGR 1900+14 with the RXTE/PCA
  42. IPN triangulation of GRB021027 (single large error box)
  43. IPN triangulation of GRB021027 (two large error boxes)
  44. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  45. GRB 021004: optical observations
  46. IPN triangulation of GRB021023 (small error boc)
  47. GRB 020813; likely host galaxy.
  48. IPN triangulation of GRB021020 (smaller error box)
  49. IPN triangulation of GRB021020
  50. GRB 021008, optical observations
  51. IPN triangulation of GRB021016 (small error box)
  52. IPN triangulation of GRB021014 (large error box)
  53. IPN triangulation of GRB021013 (single error box)
  54. GRB 021004: optical spectroscopy on Oct 11
  55. IPN triangulation of GRB021013 (two small error boxes)
  56. GRB021004: High-resolution optical spectroscopy
  57. XRF 020903: flattening of the optical light curve.
  58. GRB021004, UBVRcIc field photometry update
  59. IPN triangulation of GRB021008 (single error box)
  60. GRB 021004 submm observations
  61. IPN triangulation of GRB021008 (two small error boxes)
  62. GRB021004 Chandra HETG Observations
  63. GRB 021004: Optical/NIR Observations
  64. GRB 021004: Additional V-band Polarimetric Observations
  65. GRB021004: optical observation
  66. GRB 021004: Host Galaxy Star Formation Rate
  67. GRB 021004 submm observations
  68. GRB 021004: WC wind?
  69. GRB021004: NIR and Optical observations
  70. GRB 021004: Optical observations, AUDE network
  71. GRB 021004 - VLA Radio Observations
  72. GRB 021004 - Unusual Radio-to-Submm Spectrum
  73. GRB 021004: optical spectroscopy
  74. IPN triangulation of GRB021007 (annulus)
  75. GRB021004: optical observations and predicted break time
  76. GRB021004: BVRc photometry
  77. GRB021004 radio observation
  78. HETE fluences for GRB021004
  79. GRB 021004: Optical Photometry at 2.5 Days
  80. GRB 021004: polarimetric observations
  81. GRB 021004: V-band Polarimetric Observations
  82. GRB021004: Update Bisei photometric data
  83. IRAM Millimeter detection of GRB 021004
  84. GRB 021004 radio observation
  85. GRB 021004: Optical Photometry at 1.5 Days
  86. GRB021004, BVRcIc field photometry
  87. GRB021004: Optical Spectroscopy
  88. GRB 021004 radio search
  89. XRF020903, BVRI field photometry
  90. XRF020903: TNG and Asiago photometry
  91. GRB 020903: Optical observations at RIKEN
  92. XRF 020903: Correction to GCN 1560
  93. XRF 020903: VRI observations
  94. XRF 020903: R band observations
  95. XRF 020903: Archival Optical Images
  96. Radio Observations of XRF 020903: The Missing Link
  97. XRF 020903: Supernova
  98. IPN triangulation of GRB020923 (two error boxes)
  99. IPN triangulation of GRB020914B
  100. IPN triangulation of GRB020911 (2 large error boxes)

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