arXiv subjects

K. Telikova

Publications and source records attributed to K. Telikova.

8 recordsLinked to original sources

arXiv2026

Multiphase images of a powerful supernova-driven wind in the early Universe

Galactic winds are considered a likely driver of rapid quenching in early massive galaxies, but until now there has been no direct evidence that such systems drive winds powerful enough to meaningfully suppress their star-formation. We present resolved cold gas and ionized gas observations of a powerful supernova-driven wind in a massive galaxy 1.1 billion years after the Big Bang (at $z$=5.3). The outflow, likely triggered by ongoing merger activity, is removing gas at twice the rate of star-formation and could plausibly eject all the cold gas from the galaxy within 100 Myr. Our results suggest that powerful merger-driven outflows may be a key mechanism to produce abundant massive quiescent galaxies in the early Universe when a large fraction of massive galaxies are interacting. The mass and energetics of this distant outflow are consistent with nearby starburst-driven superwinds, suggesting that the efficiency of stellar feedback has remained relatively constant over the last 12 billion years of cosmic history.

astro-ph.GA↗

arXiv2025

The ALMA-CRISTAL survey: Gas, dust, and stars in star-forming galaxies when the Universe was ~1 Gyr old I. Survey overview and case studies

We present the ALMA-CRISTAL survey, an ALMA Cycle 8 Large Program designed to investigate the physical properties of star-forming galaxies at $4 \lesssim z \lesssim 6$ through spatially resolved, multi-wavelength observations. This survey targets 19 star-forming main-sequence galaxies selected from the ALPINE survey, using ALMA Band 7 observations to study [CII] 158 $\mu$m line emission and dust continuum, complemented by JWST/NIRCam and HST imaging to map stellar and UV emission. The CRISTAL sample expanded to 39 after including newly detected galaxies in the CRISTAL fields, archival data, and pilot study targets. The resulting dataset provides a detailed view of gas, dust, and stellar structures on kiloparsec scales at the end of the era of reionization. The survey reveals diverse morphologies and kinematics, including rotating disks, merging systems, [CII] emission tails from potential interactions, and clumpy star formation. Notably, the [CII] emission in many cases extends beyond the stellar light seen in HST and JWST imaging. Scientific highlights include CRISTAL-10, exhibiting an extreme [CII] deficit similar to Arp 220; and CRISTAL-13, where feedback from young star-forming clumps likely causes an offset between the stellar clumps and the peaks of [CII] emission. CRISTAL galaxies exhibit global [CII]/FIR ratios that decrease with increasing FIR luminosity, similar to trends seen in local galaxies but shifted to higher luminosities, likely due to their higher molecular gas content. CRISTAL galaxies also span a previously unexplored range of global FIR surface brightness at high-redshift, showing that high-redshift galaxies can have elevated [CII]/FIR ratios. These elevated ratios are likely influenced by factors such as lower metallicity gas, the presence of significant extraplanar gas, and contributions from shock-excited gas.

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arXiv2024

The ALMA-CRISTAL Survey: Complex kinematics of the galaxies at the end of the Reionization Era

The history of gas assembly in early galaxies is reflected in their complex kinematics. While a considerable fraction of galaxies at z~5 are consistent with rotating disks, current studies indicate that the dominant galaxy assembly mechanism corresponds to mergers. Despite the important progress, the dynamical classification of galaxies at these epochs is still limited by observations' resolution. We present a detailed morphological and kinematic analysis of the far-infrared bright main sequence galaxy HZ10 at z=5.65, making use of new high-resolution ($\lesssim0.3$") [CII] 158$\mu$m ALMA and rest-frame optical JWST/NIRSpec observations. These observations reveal a previously unresolved complex morphology and kinematics of the HZ10. We confirm that HZ10 is not a single galaxy but consists of at least three components in close projected separation along the east-to-west direction. We find a [CII] bright central component (C), separated by 1.5 and 4 kpc from the east (E) and west (W) components, respectively. Our [CII] observations resolve the HZ10-C component resulting in a velocity gradient, produced by either rotation or a close-in merger. We test the rotating disk possibility using DysmalPy kinematic modeling and propose three dynamical scenarios for the HZ10 system: (i) a double merger, in which the companion galaxy HZ10-W merges with the disturbed clumpy rotation disk formed by the HZ10-C and E components; (ii) a triple merger, where the companion galaxies, HZ10-W and HZ10-E, merge with the rotation disk HZ10-C; and (iii) a quadruple merger, in which the companion galaxies HZ10-W and HZ10-E merge with the close double merger HZ10-C. Comparing [CII] with JWST/NIRSpec data, we find that [CII] emission closely resembles the broad [OIII] 5007{\AA} emission. The latter reflects the interacting nature of the system and suggests that ionized and neutral gas phases in HZ10 are well mixed.

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arXiv2024

A hidden active galactic nucleus powering bright [O III] nebulae in a protocluster at $z=4.5$ revealed by JWST

Galaxy protoclusters are sites of rapid growth, with a high density of massive galaxies driving elevated rates of star formation and accretion onto supermassive black holes. Here, we present new JWST/NIRSpec IFU observations of the J1000+0234 group at $z=4.54$, a dense region of a protocluster hosting a massive, dusty star forming galaxy (DSFG). The new data reveal two extended, high-equivalent-width (EW$_0>1000\r{A}$) [O III] nebulae that appear at both sides of the DSFG along its minor axis (namely O3-N and O3-S). On one hand, the spectrum of O3-N shows a broad and blueshifted component with a full width at half maximum (FWHM) of 1300 km/s, suggesting an outflow origin. On the other hand, O3-S stretches over 8.6 kpc, and has a velocity gradient that spans 800 km/s, but shows no evidence of a broad component. However, both sources seem to be powered by an active galactic nucleus (AGN), so we classified them as extended emission-line regions (EELRs). The strongest evidence comes from the detection of the high-ionization [Ne V] $\lambda 3427$ line toward O3-N, which paired with the lack of hard X-rays implies an obscuring column density above the Compton-thick regime. The [Ne V] line is not detected in O3-S, but we measure a He II $\lambda 4687$/H$\beta$=0.25, which is well above the expectation for star formation. Despite the remarkable alignment of O3-N and O3-S with two radio sources, we do not find evidence of shocks from a radio jet that could be powering the EELRs. We interpret this as O3-S being externally irradiated by the AGN, akin to the famous Hanny's Voorwerp object in the local Universe. In addition, classical line ratio diagnostics (e.g., [O III]/H$\beta$ vs [N II]/H$\alpha$) put the DSFG itself in the AGN region of the diagrams, and therefore suggest it to be the most probable AGN host. These results showcase the ability of JWST to unveil obscured AGN at high redshifts.

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arXiv2024

The ALMA-CRISTAL survey: Dust temperature and physical conditions of the interstellar medium in a typical galaxy at z=5.66

We present new $\lambda_{\rm rest}=77$ $\mu$m dust continuum observations from the ALMA of HZ10 (CRISTAL-22), a dusty main-sequence galaxy at $z$=5.66 as part of the [CII] Resolved Ism in STar-forming Alma Large program, CRISTAL. The high angular resolution of the ALMA Band 7 and new Band 9 data($\sim{0}''.4$) reveals the complex structure of HZ10, which comprises two main components (HZ10-C and HZ10-W) and a bridge-like dusty emission between them (the Bridge). We model the dust spectral energy distribution (SED) to constrain the physical conditions of the interstellar medium (ISM) and its variations among the different components identified in HZ10. We find that HZ10-W (the more UV-obscured component) has an SED dust temperature of $T_{\rm SED}$$\sim$51.2$\pm13.1$ K; this is $\sim$5 K higher (although still consistent) than that of the central component and previous global estimations for HZ10. Our new ALMA data allow us to reduce by a factor of $\sim$2.3 the uncertainties of global $T_{\rm SED}$ measurements compared to previous studies. Interestingly, HZ10-W shows a lower [CII]/FIR ratio compared to the other two components (although still within the uncertainties), suggesting a harder radiation field destroying polycyclic aromatic hydrocarbon associated with [CII] emission (e.g., active galactic nuclei or young stellar populations). While HZ10-C appears to follow the tight IRX-$\beta_{\rm UV}$ relation seen in local UV-selected starburst galaxies and high-$z$ star-forming galaxies, we find that both HZ10-W and the Bridge depart from this relation and are well described by dust-screen models with holes in front of a hard UV radiation field. This suggests that the UV emission (likely from young stellar populations) is strongly attenuated in the more dusty components of the HZ10 system.

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arXiv2024

The ALMA-CRISTAL survey: Extended [CII] emission in an interacting galaxy system at z ~ 5.5

The ALMA [CII] Resolved Ism in STar-forming gALaxies (CRISTAL) survey is a Cycle 8 ALMA Large Programme that studies the cold gas component of high-redshift galaxies. Its sub-arcsecond resolution observations are key to disentangling physical mechanisms that shape galaxies during cosmic dawn. In this paper, we explore the morphology and kinematics of the cold gas, star-forming, and stellar components in the star-forming main-sequence galaxy CRISTAL-05/HZ3, at z = 5.54. Our analysis includes 0.3" spatial resolution (~2 kpc) ALMA observations of the [CII] line. While CRISTAL-05 was previously classified as a single source, our observations reveal that the system is a close interacting pair surrounded by an extended component of carbon-enriched gas. This is imprinted in the disturbed elongated [CII] morphology and the separation of the two components in the position-velocity diagram (~100 km/s). The central region is composed of two components, named C05-NW and C05-SE, with the former being the dominant one. A significant fraction of the [CII] arises beyond the close pair up to 10 kpc, while the regions forming new massive stars and the stellar component seem compact (r_[CII] ~ 4 r_UV), as traced by rest-frame UV and optical imaging obtained with the Hubble Space Telescope and the James Webb Space Telescope. Our kinematic model, using the DYSMALpy software, yields a minor contribution of dark matter of C05-NW within a radius of ~2x Reff. Finally, we explore the resolved [CII]/FIR ratios as a proxy for shock-heating produced by this merger. We argue that the extended [CII] emission is mainly caused by the merger, which could not be discerned with lower-resolution observations. Our work emphasizes the need for high-resolution observations to fully characterize the dynamic stages of infant galaxies and the physical mechanisms that drive the metal enrichment of the circumgalactic medium.

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arXiv2024

The ALMA-CRISTAL survey. Discovery of a 15 kpc-long gas plume in a $z=4.54$ Lyman-$\alpha$ blob

Massive star-forming galaxies in the high-redshift universe host large reservoirs of cold gas in their circumgalactic medium (CGM). Traditionally, these reservoirs have been linked to diffuse H I Lyman-$\alpha$ (Ly$\alpha)$ emission extending beyond $\approx 10$ kpc scales. In recent years, millimeter/submillimeter observations are starting to identify even colder gas in the CGM through molecular and/or atomic tracers such as the [C II] $158\,\mu$m transition. In this context, we study the well-known J1000+0234 system at $z=4.54$ that hosts a massive dusty star-forming galaxy (DSFG), a UV-bright companion, and a Ly$\alpha$ blob. We combine new ALMA [C II] line observations taken by the CRISTAL survey with data from previous programs targeting the J1000+0234 system, and achieve a deep view into a DSFG and its rich environment at a 0.2" resolution. We identify an elongated [C II]-emitting structure with a projected size of 15 kpc stemming from the bright DSFG at the center of the field, with no clear counterpart at any other wavelength. The plume is oriented $\approx 40^{\circ}$ away from the minor axis of the DSFG, and shows significant spatial variation of its spectral parameters. In particular, the [C II] emission shifts from 180 km/s to 400 km/s between the bottom and top of the plume, relative to the DSFG's systemic velocity. At the same time, the line width starts at 400-600 km/s but narrows down to 190 km/s at top end of the plume. We discuss four possible scenarios to interpret the [C II] plume: a conical outflow, a cold accretion stream, ram pressure stripping, and gravitational interactions. While we cannot strongly rule out any of these with the available data, we disfavor the ram pressure stripping scenario due to the requirement of special hydrodynamic conditions.

astro-ph.GA↗

arXiv2021

Sharpening quasar absorption lines with ESPRESSO: Temperature of warm gas at $z\sim2$, constraints on the Mg isotopic ratio, and structure of cold gas at $z\sim0.5$

We present a high-resolution (R=140,000) spectrum of the bright quasar HE0001-2340 (z=2.26), obtained with ESPRESSO at the Very Large Telescope. We analyse three systems at z=0.45, z=1.65, and z=2.19 using multiple-component Voigt-profile fitting. We also compare our spectrum with those obtained with VLT/UVES, covering a total period of 17 years. We disentangle turbulent and thermal broadening in many components spread over about 400 km/s in the z~2.19 sub-DLA system. We derive an average temperature of 16000+/-1300 K, i.e., about twice the canonical value of the warm neutral medium in the Galactic interstellar medium. A comparison with other high-z, low-metallicity absorbers reveals an anti-correlation between gas temperature and total HI column density. Although requiring confirmation, this could be the first observational evidence of a thermal decrease with galacto-centric distance, i.e., we may be witnessing a thermal transition between the circum-galactic medium and the cooler ISM. We revisit the Mg isotopic ratios at z=0.45 and z=1.65 and constrain them to be xi = (26Mg+25Mg)/24Mg <0.6 and <1.4 in these two systems, respectively. These values are consistent with the standard Solar ratio, i.e., we do not confirm strong enhancement of heavy isotopes previously inferred from UVES data. Finally, we confirm the partial coverage of the quasar emission-line region by a FeI-bearing cloud in the z=0.45 system and present evidence for velocity sub-structure of the gas that has Doppler parameters of the order of only ~0.3 km/s. This work demonstrates the uniqueness of high-fidelity, high-resolution optical spectrographs on large telescopes as tools to investigate the thermal state of the gas in and around galaxies as well as its spatial and velocity structure on small scales, and to constrain the associated stellar nucleosynthetic history. [abridged]

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