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Related papers: Strong Clustering in the Low Redshift Lyman-$\alph…

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We use new observations of very weak CIV absorption lines associated with high-redshift Lyman-alpha absorption systems to measure the high-redshift Lyman-alpha line two-point correlation function (TPCF). These very weak CIV absorption lines…

Astrophysics · Physics 2009-10-28 A. Fernandez-Soto , K. M. Lanzetta , X. Barcons , R. F. Carswell , J. K. Webb , A. Yahil

We present a search for spatial and redshift correlations in a 2 A resolution spectroscopic survey of the Lyman alpha forest at 2.15 < z < 3.37 toward ten QSOs concentrated within a 1-degree diameter field. We find a signal at 2.7 sigma…

Astrophysics · Physics 2009-10-31 G. M. Williger , A. Smette , C. Hazard , J. A. Baldwin , R. G. McMahon

We present a novel technique for calculating the two-point autocorrelation function of the Lyman-alpha forest based on the relation between the two-point correlation function and the Neighbor Probability Distribution Functions. The…

Astrophysics · Physics 2009-10-28 Avery Meiksin , Francois R. Bouchet

The spatial distribution of Ly-alpha forest absorption systems towards ten QSOs has been analysed to search for large-scale structure over the redshift range 2.2 < z < 3.4. The QSOs form a closely spaced group on the sky and are…

Astrophysics · Physics 2009-10-31 J. Liske , J. K. Webb , G. M. Williger , A. Fernandez-Soto , R. F. Carswell

Spectroscopy with HST/STIS Echelle and VLT/UVES of the bright QSO HE 0515-4414 (z_em =1.73, B = 15.0) offers for the first time the opportunity to study the Lyman alpha forest in the redshift range 0.9 < z < 1.7 at a resolution ~ 10 km/s.…

Astrophysics · Physics 2009-11-07 Eckart Janknecht , Robert Baade , Dieter Reimers

We study the evolution with redshift of the number density of Ly$\alpha$ clouds in a CDM model using numerical simulations including photo-ionization and cooling of the baryonic component. The photo-ionizing flux is consistently taken as…

Astrophysics · Physics 2019-08-17 Jan P. Mücket , Patrick Petitjean , Ronald E. Kates , Rüdiger Riediger

We present HST STIS observations of four quasar pairs with redshifts 0.84<z_em<1.56 and angular separation 2-3 arcmin corresponding to ~ 1-1.5 h^-1_50 Mpc transverse proper distance at z ~ 0.9. We study the distribution of velocity…

Astrophysics · Physics 2009-11-07 B. Aracil , P. Petitjean , A. Smette , J. Surdej , J. P. Mucket , S. Cristiani

We analyze the clustering properties of a high-resolution (~10 km/s) sample of about 1600 Lyman-alpha lines in the spectra of 15 quasars, obtained in the framework of an ESO key-programme with the addition of literature data. The two-point…

Astrophysics · Physics 2015-06-24 S. Cristiani , S. D'Odorico , V. D'Odorico , A. Fontana , E. Giallongo , S. Savaglio

The flux/transmission power spectrum has become a popular statistical tool in studies of the high redshift ($z > 2$) Lyman-alpha forest. At low redshifts, where the forest has thinned out into a series of well-isolated absorption lines, the…

Astrophysics · Physics 2016-01-27 Lam Hui

Using high resolution (R ~ 45000), high S/N (20-50) VLT/UVES observations covering the Lyman-alpha forest at 1.5 < z < 2.4 combined with similar observations at z > 2.4 from the literature, we have presented the redshift evolution of the…

Astrophysics · Physics 2009-11-06 Tae-Sun Kim , Stefano Cristiani , Sandro D'Odorico

We present STIS 7km/s resolution data of the Ly-a forest toward PKS0405-123 (z=0.574). We make two samples. The strong sample (60 systems) has column density logNHI>13.3 over 0.002<z<0.423, and the weak sample (44) has logNHI>13.1 at…

Combining a new, increased dataset of 8 QSOs covering the Ly-alpha forest at redshifts 1.5 < z < 3.6 from VLT/UVES observations with previously published results, we have investigated the properties of the Ly-alpha forest at 1.5 < z < 4. We…

We present observations of the Lyman alpha forest towards B2 1225+317 taken at a resolution of 18 km/s. A clean sample of Lyman alpha forest lines is extracted after a careful profile fitting analysis and removal of absorption lines of…

Astrophysics · Physics 2015-06-24 Pushpa Khare , R. Srianand , D. G. York , R. Green , D. Welty , Ke-Liang Huang , J. Bechtold

Separating the cosmological redshifted 21-cm signal from foregrounds is a major challenge. We present the cross-correlation of the redshifted 21-cm emission from neutral hydrogen (HI) in the post-reionization era with the Ly-alpha forest as…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Tapomoy Guha Sarkar , Somnath Bharadwaj , Tirthankar Roy Choudhury , Kanan Datta

We study the three-dimensional distribution of non virialised matter at z~2 using high resolution spectra of QSO pairs and simulated spectra drawn from cosmological hydrodynamical simulations. We have collected the largest sample of QSO…

Astrophysics · Physics 2009-11-11 V. D'Odorico , M. Viel , F. Saitta , S. Cristiani , S. Bianchi , B. Boyle , S. Lopez , J. Maza , P. Outram

While the Lyman-$\alpha$ (Ly$\alpha$) forest traces the large-scale matter distribution over a wide range of redshift, its three-dimensional (3D) clustering at $z < 2$ has not yet been measured. We investigate the prospects for measuring…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-23 Ting Tan , Huanyuan Shan , Eric Armengaud

We present a study of the spatial coherence of the intergalactic medium toward two pairs of high-redshift quasars with moderate angular separations observed with Keck/ESI, Q1422+2309A/Q1424+2255 (z_em = 3.63, theta = 39") and Q1439-0034A/B…

Astrophysics · Physics 2009-11-10 George D. Becker , Wallace L. W. Sargent , Michael Rauch

We explore the feasibility of using Lyman-$\alpha$ (Ly$\alpha$) forests to calibrate the ensemble redshift distribution of the high-redshift tail ($2<z<3$) of photometric galaxies. We use \texttt{CoLoRe} simulations to create mock DESI…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-12 Qianjun Hang , Laura Casas , William d'Assignies , Wynne Turner , Andreu Font-Ribera , Benjamin Joachimi

The quasar in the Hubble Deep Field South (HDFS), J2233-606 (z=2.23) has been exhaustively observed by ground based telescopes and by the STIS spectrograph on board the Hubble Space Telescope at low, medium and high resolution in the…

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