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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"

27396 results found.

  1. VLT spectra of GRB 030328
  2. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  3. GRB 030328: Optical observations
  4. GRB030324 optical observation
  5. GRB030131, BVRcIc field photometry
  6. Possible GRB030323 localized by INTEGRAL
  7. GRB030323: Detection on 2003/03/24
  8. IPN triangulation of GRB030326 (single small error box)
  9. IPN triangulation of GRB030325 (two small error boxes)
  10. GRB030323: V, R, I photometry
  11. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  12. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  13. VLT/FORS2 spectra of GRB 030323
  14. GRB030323, optical observations
  15. GRB030324, BVRcIc field photometry
  16. GRB030323, BVRcIc field calibration
  17. IPN triangulation of GRB030320 (small error box)
  18. Possible GRB 030320 localized by INTEGRAL
  19. IPN triangulation of GRB030306 (single small error box - REVISED)
  20. IPN triangulation of GRB030306 (single small error box)
  21. IPN triangulation of GRB030306 (two small error boxes)
  22. GRB030226, BVRc observations
  23. Chandra detection of the X-ray afterglow of GRB 030226
  24. GRB030227: Kiso optical upper limit
  25. GRB030227, BVRcIc field photometry
  26. GRB030226, BVRcIc field calibration
  27. GRB 030228, optical observations
  28. GRB 030227: Confirmed Optical Afterglow (S1-A)
  29. GRB 030227: fading of candidate optical afterglow 'S1-A'
  30. GRB030227:Optical observations
  31. GRB 030227, possible optical counterpart of XMM-Newton source
  32. GRB030227 - faint tentative OT candidate
  33. GRB 030226, optical observations
  34. XMM-Newton observation of GRB030227
  35. GRB030227: Kiso optical observations
  36. GRB 030227: Kyoto optical observation
  37. GRB 030226, optical light curve
  38. GRB030227 localized by INTEGRAL
  39. GRB 030226 : Predicted light curve
  40. GRB030226: ESI spectroscopy
  41. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  42. GRB 030226 simultaneous optical observations
  43. GRB 030226, optical observations
  44. GRB030226: Optical decay index
  45. GRB 030226 Optical Spectra and R,I,z' Imaging
  46. GRB: Non-Referencing of GCN Circulars.
  47. IPN triangulation of GRB030217 (small error box)
  48. GRB 030131: marginal optical detection
  49. GRB 030204: Optical Observations
  50. GRB030204 field photometry
  51. GRB020819: Kiso R and I band observations
  52. GRB030131: Candidate Optical Afterglow
  53. IPN triangulation of GRB030204 (small error box)
  54. GRB 030131, optical observations
  55. GRB 030131: afterglow candidate
  56. GRB 030115, late-time optical observations
  57. GRB030131: corrected INTEGRAL position
  58. GRB 020819: Host galaxy at Radio Position
  59. IPN triangulation of GRB030131
  60. GRB 030131 optical observations
  61. GRB 030131 optical observations
  62. A long GRB detected by INTEGRAL
  63. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  64. GRB 030115, simultaneous observations by BOOTES-1
  65. GRB 030115: IR observations with IRSF/SIRIUS
  66. IPN triangulation of GRB030115C (large error box)
  67. GRB030115, afterglow candidate
  68. GRB 021211: R-band observations at late-time
  69. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  70. GRB 030115 : Possible IR counterpart
  71. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  72. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  73. GRB 030115: APO Optical Observations
  74. Information about where HETE will be pointing
  75. VLT spectroscopy of the probable host of GRB 021211
  76. IPN triangulation of GRB030101 (two large error boxes)
  77. GRB 021211: Probable Host and Underlying Supernova
  78. GRB 021112: Evidence for Another Dark Optical Afterglow
  79. GRB 021219: OSN optical observations
  80. GRB021219, optical observations
  81. GRB021219, optical observation by MASTER
  82. VLT spectra of GRB 021211 revisited
  83. GRB021219: a long GRB localized by INTEGRAL
  84. GRB021211: APO optical observations
  85. XRF 020903 : HST observations
  86. GRB 021201: Optical Observations
  87. GRB 021211: CTIO observations
  88. GRB021211, BVRI field photometry
  89. GRB021211: Optical observations in CrAO
  90. GRB 021211, optical observations
  91. GRB021211: Kiso Observations
  92. GRB 021201, optical observations
  93. GRB021211: Optical observations
  94. GRB 021201 (short/hard), NOT observations
  95. SUB-MM SEARCH FOR GRB 021211
  96. Chandra observation of the IPN error box of GRB021201 (short/hard)
  97. GRB 021211, R- and I-band observations
  98. GRB021211 - Upper limits from recent and historical observations
  99. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  100. IPN triangulation of GRB021206 (small error box)

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