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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"

27322 results found.

  1. VLT spectroscopy of the probable host of GRB 021211
  2. IPN triangulation of GRB030101 (two large error boxes)
  3. GRB 021211: Probable Host and Underlying Supernova
  4. GRB 021112: Evidence for Another Dark Optical Afterglow
  5. GRB 021219: OSN optical observations
  6. GRB021219, optical observations
  7. GRB021219, optical observation by MASTER
  8. VLT spectra of GRB 021211 revisited
  9. GRB021219: a long GRB localized by INTEGRAL
  10. GRB021211: APO optical observations
  11. XRF 020903 : HST observations
  12. GRB 021201: Optical Observations
  13. GRB 021211: CTIO observations
  14. GRB021211, BVRI field photometry
  15. GRB021211: Optical observations in CrAO
  16. GRB 021211, optical observations
  17. GRB021211: Kiso Observations
  18. GRB 021201, optical observations
  19. GRB021211: Optical observations
  20. GRB 021201 (short/hard), NOT observations
  21. SUB-MM SEARCH FOR GRB 021211
  22. Chandra observation of the IPN error box of GRB021201 (short/hard)
  23. GRB 021211, R- and I-band observations
  24. GRB021211 - Upper limits from recent and historical observations
  25. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  26. IPN triangulation of GRB021206 (small error box)
  27. IPN triangulation of GRB021205 (large error box)
  28. GRB021201, BVRcIc field photometry
  29. GRB 021201: BOOTES simultaneous optical observations
  30. IPN triangulation of GRB021201 (short/hard burst, small error box)
  31. GRB021004, late time optical observations
  32. GRB021004 Chandra Observation
  33. IPN detection of continued SGR1900+14 activity
  34. Improved IPN error box for GRB021125
  35. IPN BURST POSITION
  36. IPN triangulation of GRB021125 (INTEGRAL BURST)
  37. GRB021125 : A long GRB localized by INTEGRAL
  38. IPN confirmation of the reactivation of SGR1900+14
  39. GRB021113, SPI ACS observation
  40. GRB 021112: Afterglow or Variable Star?
  41. GRB021113: optical observations at Bisei
  42. GRB 021113: Evidence for a Dark Optical Afterglow
  43. GRB021112, BVRI field photometry
  44. GRB 021112: Variable Source in R-band search
  45. GRB021112: Optical Observations
  46. IPN triangulation of GRB021113 (=H2449; annulus)
  47. GRB 021113: Optical observations
  48. GRB 021112: RAPTOR Observations
  49. GRB021113 (=H2449): A Long GRB Localized by HETE
  50. GRB021112 (=H2448): A Long GRB Localized by HETE
  51. GRB 021016: Optical Observations
  52. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  53. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  54. SGR1900+14 activity, November 2-4, 2002
  55. GRB021104: optical observations
  56. Detection of activity from SGR 1900+14 with the RXTE/PCA
  57. IPN triangulation of GRB021027 (single large error box)
  58. IPN triangulation of GRB021027 (two large error boxes)
  59. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  60. GRB 021004: optical observations
  61. IPN triangulation of GRB021023 (small error boc)
  62. GRB 020813; likely host galaxy.
  63. IPN triangulation of GRB021020 (smaller error box)
  64. IPN triangulation of GRB021020
  65. GRB 021008, optical observations
  66. IPN triangulation of GRB021016 (small error box)
  67. IPN triangulation of GRB021014 (large error box)
  68. IPN triangulation of GRB021013 (single error box)
  69. GRB 021004: optical spectroscopy on Oct 11
  70. IPN triangulation of GRB021013 (two small error boxes)
  71. GRB021004: High-resolution optical spectroscopy
  72. XRF 020903: flattening of the optical light curve.
  73. GRB021004, UBVRcIc field photometry update
  74. IPN triangulation of GRB021008 (single error box)
  75. GRB 021004 submm observations
  76. IPN triangulation of GRB021008 (two small error boxes)
  77. GRB021004 Chandra HETG Observations
  78. GRB 021004: Optical/NIR Observations
  79. GRB 021004: Additional V-band Polarimetric Observations
  80. GRB021004: optical observation
  81. GRB 021004: Host Galaxy Star Formation Rate
  82. GRB 021004 submm observations
  83. GRB 021004: WC wind?
  84. GRB021004: NIR and Optical observations
  85. GRB 021004: Optical observations, AUDE network
  86. GRB 021004 - VLA Radio Observations
  87. GRB 021004 - Unusual Radio-to-Submm Spectrum
  88. GRB 021004: optical spectroscopy
  89. IPN triangulation of GRB021007 (annulus)
  90. GRB021004: optical observations and predicted break time
  91. GRB021004: BVRc photometry
  92. GRB021004 radio observation
  93. HETE fluences for GRB021004
  94. GRB 021004: Optical Photometry at 2.5 Days
  95. GRB 021004: polarimetric observations
  96. GRB 021004: V-band Polarimetric Observations
  97. GRB021004: Update Bisei photometric data
  98. IRAM Millimeter detection of GRB 021004
  99. GRB 021004 radio observation
  100. GRB 021004: Optical Photometry at 1.5 Days

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