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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').
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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"
  1. GRB 030329 Oprical observations in Rozhen observatory
  2. GRB 030429: ROTSE-III observations
  3. GRB 030324: Radio Observations
  4. GRB030329 observed as a sudden ionospheric disturbance (SID)
  5. IPN triangulation of GRB030426 (annulus)
  6. SNeIa AS THE POSSIBLE PROGENITORS OF SHORT-DURATION GRBs.
  7. IPN triangulation of GRB030425 (single error box)
  8. GRB030329, SPM optical observations (Correction)
  9. GRB030329, SPM optical observations
  10. GRB 030329, the review of the sky area in plate archive (1950-1998)
  11. GRB 030329: Spectral Evolution of SN 2003dh
  12. Optical Observations of GRB 030418 with Magellan
  13. GRB 030329: optical spectropolarimetry at VLT
  14. IPN triangulation of GRB030422C (annulus)
  15. IPN triangulation of GRB030422B (annulus)
  16. GRB 030329: wide-field photograph by R. Tamura 1 hr after the burst
  17. GRB030329: optical polarization
  18. IPN triangulation of GRB030422 (two large error boxes)
  19. GRB 030329 3.5 and 6 cm radio observations at RTF-32 telescope
  20. GRB030329, optical observation
  21. IPN triangulation of GRB030421 (annulus)
  22. MASTER:optical observations GRB030418
  23. MASTER:optical observations probable GRB030414
  24. GRB030329: 444 AAVSO Measurements
  25. IPN triangulation of GRB030419 (annulus)
  26. MASTER:optical observations GRB030416
  27. ROTSE-III prompt optical detections of GRB 030418
  28. GRB030418: Upper limits from recent and historical observations.
  29. GRB030418: Kiso near infrared observations
  30. GRB 030418: Optical afterglow
  31. GRB 030418: Finder for afterglow candidate
  32. GRB 030418: Optical afterglow candidate
  33. GRB 030329 OT position
  34. GRB030329: Optical Observations
  35. OT GRB 030329: early UBVRcIc spectral evolution
  36. GRB030329, UBVRI polarimetry, R-polarization
  37. GRB 030329: SARA Optical Observations
  38. OT GRB 030329: early spectrum
  39. GRB030329: VR Photometry at TNG
  40. GRB030324: Candidate Optical Afterglow (Erratum)
  41. GRB030324: Candidate Optical Afterglow
  42. IPN triangulation of GRB030414 (small error box)
  43. GRB 030413: Optical Observations
  44. GRB 030329 Rc observations
  45. IPN triangulation of GRB030413 (small error box)
  46. IPN triangulation of GRB030410 (annulus)
  47. Superluminal motion in GRB 030329 (Correction)
  48. Superluminal motion in GRB 030329
  49. GRB 030329 and SN 2003dh
  50. GRB030329, optical position
  51. GRB 030329 VLBA Observations
  52. CORRECTION TO IPN TRIANGULATION OF GRB050403
  53. IPN triangulation of GRB030406 (small error box)
  54. IPN triangulation of GRB050403 (small error box)
  55. IPN triangulation of GRB030403 (annulus)
  56. GRB 030329: BVRI photometry at Asiago
  57. GRB 030329, light curve flattens
  58. GRB 030329: VLT V-band photometry
  59. If the SN/GRB connection confirmed
  60. GRB 030329: Supernova Confirmed
  61. GRB030329: RTT150 optical observations
  62. GRB030329: Near Infrared Observations at Gunma
  63. GRB030329: HET spectroscopic monitoring
  64. Kiso observation of the GRB030329 at April 6
  65. GRB 030329, color evolution
  66. GRB030328, UBVRcIc field photometry
  67. GRB030329: Optical observcations
  68. GRB030329: BV photographic observations
  69. GRB 030329 Optical observations
  70. GRB 030329, color evolution
  71. GRB 030329: possible color change
  72. GRB030329: RTT150 optical observations
  73. GRB 030329: Supernova Spectrum Emerging
  74. GRB030329: Kiso B and R band observations
  75. GRB030329: RTT150 optical observation
  76. GRB030329: More AAVSO VR obs
  77. GRB030328: R upper limit after 6 hours by MASTER
  78. GRB 030329: BV photographic observations
  79. GRB 030329: SARA Optical Observations
  80. GRB 030329: SARA Optical Observations
  81. GRB030329, fading resumes
  82. GRB 030329, BVRI photometry
  83. GRB030329: Optical observations
  84. SDSS 0.5m PT observations of GRB030329 (correction)
  85. SDSS 0.5m PT observations of GRB030329
  86. GRB 030329, Optical observations
  87. GRB 030329, nearby galaxies
  88. GRB030329, cessation of fading
  89. GRB030329: final R-band light curve by MASTER
  90. GRB030329 - more 15 GHz radio data
  91. GRB030329 Radio 23/43/90 GHz observations at Nobeyama
  92. GRB 030329: Sub-millimeter detection
  93. GRB 030329: SARA Optical Observations
  94. GRB 030329: SARA Optical Observations
  95. OT GRB light curves and SN predictions
  96. GRB030329, optical observation
  97. GRB030329, optical observation
  98. GRB030329, new UBVRcIc field photometry
  99. GRB 030329, light curve and SN prediction
  100. GRB030329: optical observations at Tokyo Tech

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