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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"

44618 results found.

  1. GRB 990510 optical observations
  2. Galactic extinction towards GRB 990510
  3. GRB990510: NFI X-ray source
  4. GRB 990510 optical observations
  5. IPN localization of GRB990510
  6. GRB 990506 Radio Observations
  7. GRB 990123, optical monitoring
  8. GRB 990506: BATSE Observations
  9. GRB 990506, optical observations
  10. GRB 990510: Final BeppoSAX-WFC Coordinates
  11. GRB 990506, Optical Observations
  12. GRB 990506 optical observations
  13. GRB 990506 optical observations
  14. GRB 990506, optical observations
  15. GRB990506 observation plan
  16. Refined IPN error box for GRB990506
  17. GRB 990506: Limits on the possible optical transient
  18. GRB 990506, armchair astronomy
  19. GRB 990506, optical observations from +1 to +3 hours
  20. GRB 990506, optical observations
  21. GRB990506 Optical observations
  22. GRB990506 observation plan
  23. New IPN/RXTE error box for GRB990506
  24. IPN localization for GRB990506
  25. GRB 970228: Redshift and properties of the host galaxy
  26. IPN localization of GRB990427
  27. GRB981220 VLBA observations
  28. GRB980425 Optical observations of exponential decline at late time
  29. GRB990321 REFINED IPN ANNULUS
  30. GRB990323 PRECISE IPN POSITION
  31. GRB990321 IPN TRIANGULATION
  32. GRB 990316 Optical Observations
  33. GRB 990316, Radio observations
  34. GRB 990316, Optical observations
  35. GRB990316, Optical observations
  36. GRB 990316 optical observations
  37. GRB990316: simultaneous optical observation
  38. GRB990316 - Optical null results
  39. ASM/IPN error box for GRB 990308 (BATSE #7457)
  40. GRB990308 not a new SGR
  41. GRB 990308a and GRB 990308b
  42. GRB990308 (Trig. 7457), optical observations
  43. GRB990308, Possible new SGR~0209+70
  44. GRB981220, IPN localization
  45. GRB 981220, radio observations
  46. GRB 990123, Field Photometry
  47. GRB 990217 Optical Observations
  48. GRB 990217, radio observations
  49. BATSE Resumes Normal Operations
  50. BATSE Flight Anomaly
  51. GRB990217: BeppoSAX/GRBM data
  52. Optical Observations of GRB990217
  53. GRB990123: Caltech STIS Photometry and Images
  54. GRB990123 observations
  55. GRB990217 Optical observation
  56. GRB990217, WFC position
  57. GRB990123, Optical Observation
  58. GRB 990123: Discovery of the Probable Host Galaxy
  59. GRB 990123: Reduced HST Images
  60. For Immediate Posting to GCN - HST Data GRB 990123 Available
  61. GRB19990123 observations
  62. GRB 990123: BVRI standards in the field
  63. GRB 990123: Updated Keck Spectroscopy Results
  64. GRB981220, field photometry
  65. GRB 990123 NOT Spectrum Update
  66. GRB990123, Optical observation
  67. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  68. GRB 990123: Publicly available reduced HST images
  69. GRB990123, Upcoming HST Service Observations
  70. GRB990123, 15-GHz limits
  71. GRB 990123: New Constraints on Possible Foreground Galaxies
  72. GRB990123 Optical Observations
  73. GRB990123, Probability of gravitational lensing
  74. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  75. GRB 990123: Continued Radio Observations
  76. GRB990123, Preliminary Lens Search Results
  77. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  78. On the Lensing Interpretation of GRB 990123
  79. Search for Potential Images of GRB 990123
  80. Search for Potential Images of GRB 990123
  81. GRB990123, Optical BVRI Observations
  82. GRB 990123: near-infrared observations.
  83. GRB990123, OSSE observations
  84. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  85. GRB990123: NIR Observation
  86. GRB990123, ASCA X-ray observation of afterglow
  87. "GRB 990123: New BV Observations"
  88. GRB 990123 Optical Follow-Up
  89. GRB 990123; Addendum to GCN 223
  90. GRB 990123: BATSE Observations
  91. GRB 990123 Keck Spectrum update
  92. GRB990123 IPN annulus
  93. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  94. GRB990123 Optical Observations
  95. GRB 990123 Spectroscopic Redshifts
  96. GRB 990123: New Optical Observations, Decay Measure
  97. GRB 990123 Optical Follow-Up
  98. GRB 990123: Possible Gravitationally Lensed Burst?
  99. GRB990123, optical observation
  100. GRB 990123 optical observations

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