Central QSO Research Articles

An AGN with an Ionized Gas Outflow in a Massive Quiescent Galaxy in a Protocluster at z = 3.09

We report the detection of an ionized gas outflow from an X-ray active galactic nucleus hosted in a massive quiescent galaxy in a protocluster at z = 3.09 (J221737.29+001823.4). It is a type-2 QSO with broad (W 80 > 1000 km s−1) and strong (/erg s−1) ≈ 43.4) [O iii]λ λ 4959,5007 emission lines detected by slit spectroscopy in three-position angles using Multi-Object Infra-Red Camera and Spectrograph (MOIRCS) on the Subaru telescope and the Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE) on the Keck-I telescope. In the all slit directions, [O iii] emission is extended to ∼15 physical kpc and indicates a powerful outflow spreading over the host galaxy. The inferred ionized gas mass outflow rate is 22 ± 3 M ⊙ yr−1. Although it is a radio source, according to the line diagnostics using Hβ, [O ii], and [O iii], photoionization by the central QSO is likely the dominant ionization mechanism rather than shocks caused by radio jets. On the other hand, the spectral energy distribution of the host galaxy is well characterized as a quiescent galaxy that has shut down star formation several hundred Myr ago. Our results suggest a scenario that QSOs are powered after the shutdown of the star formation and help complete the quenching of massive quiescent galaxies at high redshift.

The Clusters Hiding in Plain Sight (CHiPS) Survey: Complete Sample of Extreme BCG Clusters

Abstract We present optical follow-up observations for candidate clusters in the Clusters Hiding in Plain Sight survey, which is designed to find new galaxy clusters with extreme central galaxies that were misidentified as bright isolated sources in the ROSAT All-Sky Survey catalog. We identify 11 cluster candidates around X-ray, radio, and mid-IR-bright sources, including six well-known clusters, two false associations of foreground and background clusters, and three new candidates, which are observed further with Chandra. Of the three new candidates, we confirm two newly discovered galaxy clusters: CHIPS 1356-3421 and CHIPS 1911+4455. Both clusters are luminous enough to be detected in the ROSAT All-Sky Survey data if not because of their bright central cores. CHIPS 1911+4455 is similar in many ways to the Phoenix cluster, but with a highly disturbed X-ray morphology on large scales. We find the occurrence rate for clusters that would appear to be X-ray-bright point sources in the ROSAT All-Sky Survey (and any surveys with similar angular resolution) to be 2% ± 1%, and the occurrence rate of clusters with runaway cooling in their cores to be <1%, consistent with predictions of chaotic cold accretion. With the number of new groups and clusters predicted to be found with eROSITA, the population of clusters that appear to be point sources (due to a central QSO or a dense cool core) could be around 2000. Finally, this survey demonstrates that the Phoenix cluster is likely the strongest cool core at z < 0.7—anything more extreme would have been found in this survey.

Black Hole-Galaxy Scaling Relation Evolution From z~2.5: Simulated Observations With HARMONI on the ELT

We present preliminary results on the potential of HARMONI, the first light integral field spectrograph for the ELT, to explore the evolution of central super massive black holes (SMBH) - host galaxy relation in the range from z∼0.7 to z∼2.5. We simulated HARMONI observations of QSO+host galaxy at different redshifts, assuming different morphologies for the host galaxy. As input, we combined MUSE observations of nearby galaxies and a theoretical QSO spectrum. These were dimmed and redshifted to the desired cosmic epoch. We scaled the total host galaxy luminosity to three different values, sampling three orders of magnitude. Likewise, we assumed two different luminosities for the central QSO. Simulations were performed for the 30×60 mas2 HARMONI spatial scale and LTAO working at 0.67 arcsec seeing. The selected wavelength range (i.e. 4700-5300 A at rest-frame) was sampled at the lowest HARMONI spectral resolving power (i.e. R∼3200). This configuration included all the ingredients to estimate the host galaxy parameters and the SMBH mass, as well as for assessing the morphological type of the host galaxy.

The concerted impact of galaxies and QSOs on the ionization and thermal state of the intergalactic medium

We present a detailed analysis of the ionization and thermal structure of the intergalactic medium (IGM) around a high-redshift QSO using a large suite of cosmological, multi-frequency radiative transfer (RT) simulations, exploring the contribution from galaxies as well as the QSO, and the effect of X-rays and secondary ionization. We show that in high-z QSO environments both the central QSO and the surrounding galaxies concertedly control the reionization morphology of hydrogen and helium and have a non-linear impact on the thermal structure of the IGM. A QSO imprints a distinctive morphology on H II regions if its total ionizing photon budget exceeds that of the surrounding galaxies since the onset of hydrogen reionization; otherwise, the morphology shows little difference from that of H II regions produced only by galaxies. In addition, the spectral shape of the collective radiation field from galaxies and QSOs controls the thickness of the I-fronts. While a UV-obscured QSO can broaden the I-front, the contribution from other UV sources, either galaxies or unobscured QSO, is sufficient to maintain a sharp I-front. X-rays photons from the QSO are responsible for a prominent extended tail of partial ionization ahead of the I-front. QSOs leave a unique imprint on the morphology of He II / He III regions. We suggest that, while the physical state of the IGM is modified by QSOs, the most direct test to understand the role of galaxies and QSOs during reionization is to perform galaxy surveys in a region of sky imaged by 21 cm tomography.

A Deep Narrow Band Imaging Search for CIVλ1548Å and HeIIλ1640Å Emission from Lyman Alpha Blobs

AbstractTo study the nature of Lyα blobs (aka LABs), we conduct a deep C IV and He II narrowband imaging survey of 13 Lyα blobs located in SSA22 proto-cluster at z ~ 3.1. We reach the unprecedented sensitivity, 5σ surface brightness limit of 2.1 − 3.4 × 10−18 erg s−1 cm−2 arcsec−2 per 1 arcsec2 aperture for two emission lines. We do not detect any extended C IV and He II emission, placing strong upper limits on the He II/Lyα and C IV/Lyα line ratios. We compare our limits with data in the literature related to the nebulae associated with high-redshift radio galaxies (HzRGs) and quasars, and we recover the data by modeling the LABs as nebulosities powered by a central QSO. For further information see Arrigoni Battaia et al. (2014).

Spectroscopy of the spatially extended Lyα emission around a quasar at z = 6.4

ABSTRACT We have taken deep, moderate-resolution Keck/DEIMOS spectra of the quasar (QSO) CFHQS J232908.28−030158.8 at z= 6.4. At the wavelength of Lyα, the spectrum shows a spatially extended component, which is significantly more extended than a stellar spectrum, and also a continuum part of the spectrum. The rest-frame linewidth of the extended component is 21 ± 7 Å and thus smaller than that of the QSO (52 ± 4 Å), where they should be identical if the light is incomplete subtraction of the QSO component. Therefore, these comparisons argue for the detection of spatially extended Lyα nebulae around this QSO. This is the first z > 6 QSO where an extended Lyα halo has been observed. Careful subtraction of the central QSO spectrum reveals a lower limit to the Lyα luminosity of (1.7 ± 0.1) × 1043 erg s−1. This emission may be from the theoretically predicted infalling gas in the process of forming a primordial galaxy that is ionized by a central QSO. On the other hand, if it is photoionized by the host galaxy, an estimated star formation rate of >3.0 M⊙ yr−1 is required. If we assume the gas is virialized, we obtain a dynamical mass estimate of Mdyn= 1.2 × 1012 M⊙. The derived MBH/Mhost ratio is 2.1 × 10−4, which is two orders of magnitude smaller than those from more massive z∼ 6 QSOs, and places this galaxy in accordance with the local MBH–σ relation, in contrast to a previous claim on the evolution of the MBH–σ relation at z∼ 6. We do not claim evolution or non-evolution of the MBH–σ relation based on a single object, but our result highlights the importance of investigating fainter QSOs at z∼ 6.

Understanding the Relations between QSOs and Their Host Galaxies from CombinedHSTImaging and VLT Spectroscopy

host galaxies of six nearby QSOs are studied on the basis of high-resolution HST optical images and spatially resolved VLT slit spectra. The gas ionization and velocity are mapped as a function of the distance to the central QSO. In the majority of the cases, the QSO significantly contributes to the gas ionization in its whole host galaxy, and sometimes even outside. Reflection or scattering of the QSO H alpha line from remote regions of the galaxy is detected in several instances. The line shifts show that, in all cases, the matter responsible for the light reflection moves away from the QSO, likely accelerated by its radiation pressure. The two faintest QSOs reside in spirals, with some signs of a past gravitational perturbation. One of the intermediate-luminosity QSOs resides in a massive elliptical containing gas ionized (and probably pushed away) by the QSO radiation. The other medium-power object is found in a spiral galaxy displaying complex velocity structure, with the central QSO moving with respect to the bulge, probably as a result of a galactic collision. The two most powerful objects are involved in violent gravitational interactions, and one of them has no detected host. These results suggest that (1) large-scale phenomena, such as galactic collisions, are closely related to the triggering and the feeding of the QSO and (2) once ignited, the QSO has significant influence on its large-scale neighborhood ( often the whole host and sometimes further away).

Extended Lyman-α emission around bright quasars

Quasars trace the most massive structures at high redshifts and their presence may influence the evolution of the massive host galaxies. We study the extended Lyman alpha emission line regions (EELRs) around seven bright, mostly radio-quiet quasars (QSOs) at 2.7<z<4.5, and compare luminosities with EELRs around radio-loud QSOs reported in the literature. Using integral field spectroscopy, we analyse the morphology and kinematics of the quiescent Lya EELRs around the QSOs. We find evidence for the presence of EELRs around four radio-quiet and one radio-loud QSO. All EELRs appear asymmetric and the optically brightest QSOs also have the brightest Lya nebulae. For the two brightest nebulae we find velocities between ~600 km s^-1 at the QSO position to ~200 km s^-1 at a distance of 3-4 arcsec from the QSO and surface flux densities up to 2-3*10^{-16} erg cm^-2 s^-1 arcsec^-2. The five EELRs have total Lya luminosities which correspond to ~0.5% of the luminosities from the QSOs broad Lya emission lines. This fraction is an order of magnitude smaller than found for EELRs around radio-loud, steep spectrum QSOs reported in the literature. While the nebulae luminosities are correlated with the QSO Lya luminosities, we find that nebulae luminosities are not correlated with the central QSO ionising fluxes. The presence of gas in the EELRs can be interpreted based on two competing scenarios: either from quasar feedback mechanisms, or from infalling matter. Apart from these two effects, the Lya flux around radio-loud objects can be enhanced due to interactions with the radio jets. The relatively fainter nebulae around radio-quiet QSOs compared to lobe-dominated radio-loud QSOs can be ascribed to this effect, or to significant differences in the environments between the two classes.

The Polarized Spectrum of the Fe [CSC]ii[/CSC]–Rich Broad Absorption Line QSO IRAS 07598+6508

We present IUE spectrophotometry and optical spectropolarimetry of the ultraluminous, extreme Fe II-emitting QSO IRAS 07598+6508. We find broad absorption troughs from high- and low-ionization species, showing that this object is a member of the class of rare low-ionization broad absorption line (BAL) QSOs. Compared with non-BAL QSOs, the spectral energy distribution is reddened by E(B - V) ~ 0.12, and the Hα/Hβ ratio is even more reddened with E(B - V) ~ 0.45. The broad emission lines are unpolarized. We see broad Na I λ5892 absorption in the unpolarized continuum, but not in the polarized continuum (at the 5-6 σ level). The polarized continuum rises smoothly toward shorter wavelengths with Fλ ∝ λ-2. We argue that a QSO continuum is polarized by scattering from a region within, or very near, the broad emission line region (BELR). Thus there are at least three distinct light paths to the observer: a dusty path from the BELR; a direct path traced by the unpolarized continuum, passing through dust and low-ionization gas (Na I); and another relatively unobscured path followed by scattered continuum. This provides direct evidence that a BAL region and dust only partially cover the central QSO. Ultraluminous active galactic nuclei, including IRAS 07598+6508, appear no more IR-luminous than non-IRAS-selected QSOs, and have LIR/Lopt ratios when the optical luminosities are corrected for reddening. BALs and reddening occur only along some sight lines, and the parent population of BAL QSOs appear to be normal QSOs.

QSOs with PHL 5200-like broad absorption line profiles

view Abstract Citations (110) References (38) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS QSOs with PHL 5200--like Broad Absorption Line Profiles Turnshek, David A. ; Foltz, Craig B. ; Grillmair, Carl J. ; Weymann, Ray J. Abstract We present moderately high resolution observations of three broad absorption line (BAL) QSOs having PHL 5200-like profiles. The objects are Q1413+113, RS 23, and PHL 5200 (the prototype of the class). These objects form a class of BAL QSOs which have relatively narrow (FWHM < 3000 km s^-1^) C IV broad emission lines (BELs) and large peak emission heights relative to the local continuum level. Relatively smooth broad absorption extends from the emission blueward out to wavelengths corresponding to as much as several tens of thousands of km s^-1^. In all of the objects studied there is some structure in the absorption troughs. This may indicate that the nature of the smooth absorption in BAL QSOs is similar to the more complex absorption that is often observed. We argue that some of the structure seen in the troughs may be due to the effects of radiation pressure. In these objects we also find that the Lyα BEL region (BELR) is occulted by the BAL region (BALR). Thus, the BALR must lie beyond the Lyα emitting region with respect to the central QSO and must also be larger in extent, as seen along our line of sight, than the Lyα emitting region. According to most models the Lyα emitting region is about 1 pc from the central engine of the QSO. We then discuss the evidence for occultation of the regions creating the high-ionization BELs of C C IV, Si IV, and N V by the BALR. Although direct examination of the C IV profile in Q1413+113 suggests that the C IV BELR is not occulted by the BALR, we reach the conclusion based on further analysis that the BALR occults all of the components of the BELR in Q1413+113. In PHL 5200 there is direct evidence that the BALR occults some of the C IV BELR. By considering the production of the N V BEL via resonance line scattering in the BALR for Q1413+113, we discuss limits on the BALR covering factor. We infer from this model and the result that the BALR occults the N V BELR that the BAL flow is decelerating. We also present observations of Q1413+113 that may show that the Si IV BAL trough has become stronger over a 4 yr period. Finally, we speculate on the nature of the large- and small-scale BALR geometry. Publication: The Astrophysical Journal Pub Date: February 1988 DOI: 10.1086/166036 Bibcode: 1988ApJ...325..651T Keywords: Absorption Spectra; Astronomical Spectroscopy; Line Spectra; Quasars; High Resolution; Lyman Alpha Radiation; Spectral Resolution; Spectrum Analysis; Astrophysics; LINE PROFILES; QUASARS full text sources ADS | data products NED (9) SIMBAD (3)