We test the use of long-wavelength dust continuum emission as a molecular gas tracer at high redshift, via a unique sample of a dozen z ∼ 2 galaxies with observations of both the dust continuum and ...CO(1−0) line emission (obtained with the Atacama Large Millimeter Array and Karl G. Jansky Very Large Array, respectively). Our work is motivated by recent high-redshift studies that measure molecular gas masses ( ) via a calibration of the rest-frame 850 m luminosity ( ) against the CO(1−0)-derived of star-forming galaxies. We therefore test whether this method is valid for the types of high-redshift, star-forming galaxies to which it has been applied. We recover a clear correlation between the rest-frame 850 m luminosity, inferred from the single-band, long-wavelength flux, and the CO(1−0) line luminosity, consistent with the samples used to perform the 850 m calibration. The molecular gas masses, derived from , agree to within a factor of two with those derived from CO(1−0). We show that this factor of two uncertainty can arise from the values of the dust emissivity index and temperature that need to be assumed in order to extrapolate from the observed frequency to the rest-frame at 850 m. The extrapolation to 850 m therefore has a smaller effect on the accuracy of derived via single-band dust-continuum observations than the assumed CO(1−0)-to- conversion factor. We therefore conclude that single-band observations of long-wavelength dust emission can be used to reliably constrain the molecular gas masses of massive, star-forming galaxies at z 2.
Abstract
We present Atacama Large Millimeter/submillimeter Array (ALMA) 2 mm continuum observations of a complete and unbiased sample of 99 870
μ
m selected submillimeter galaxies (SMGs) in the ...Extended Chandra Deep Field South (ALESS). Our observations of each SMG reach average sensitivities of 53
μ
Jy beam
−1
. We measure the flux densities for 70 sources, for which we obtain a typical 870
μ
m-to-2 mm flux ratio of 14 ± 5. We do not find a redshift dependence of this flux ratio, which would be expected if the dust emission properties of our SMGs were the same at all redshifts. By combining our ALMA measurements with existing Herschel/SPIRE observations, we construct a (biased) subset of 27 galaxies for which the cool dust emission is sufficiently well sampled to obtain precise constraints on their dust properties using simple isothermal models. Thanks to our new 2 mm observations, the dust emissivity index is well constrained and robust against different dust opacity assumptions. The median dust emissivity index of our SMGs is
β
≃ 1.9 ± 0.4, consistent with the emissivity index of dust in the Milky Way and other local and high-redshift galaxies, as well as classical dust-grain model predictions. We also find a negative correlation between the dust temperature and
β
, similar to low-redshift observational and theoretical studies. Our results indicate that
β
≃ 2 in high-redshift dusty star-forming galaxies, implying little evolution in dust-grain properties between our SMGs and local dusty galaxy samples, and suggesting that these high-mass and high-metallicity galaxies have dust reservoirs driven by grain growth in their interstellar medium.
► We studied skin conductance responses (SCR) to different gaze conditions. ► Eye contact evoked enhanced SCRs compared to averted gaze or closed eyes. ► This result applied both for short (2
s) and ...long (5
s) stimulus presentation times. ► In a self-timing condition, averted gaze was looked at longer than direct gaze. ► Direct gaze was approachable for those scoring high on emotional stability.
The present study investigated the effect of stimulus duration on skin conductance responses (SCRs) evoked by different gaze directions of a live person. In two separate parts of the experiment, either two fixed stimulus durations (2
s and 5
s) or a participant-controlled stimulus duration was used. The results showed that the eye contact evoked enhanced SCRs compared to averted gaze or closed eyes conditions irrespective of the presentation time. Subjective evaluations of approach–avoidance-tendencies indicated that the direct gaze elicited either approach or avoidance, depending on the participant. Participants who had evaluated a direct gaze-condition as approachable were found to be more emotionally stabile than those who had evaluated the same condition as avoidable. In the self-timing condition, averted gaze was looked at longer than direct gaze. Our results suggest that direct gaze, also when encountered only briefly like in every-day social encounterings, increases autonomic sympathetic arousal.
Galaxy mergers play a critical role in galaxy evolution. They alter the size, morphology, dynamics, and composition of galaxies. Galaxy mergers have so far mostly been identified through visual ...inspection of their rest-frame optical and near-IR (NIR) emission. Dust can obscure this emission, however, resulting in the misclassification of mergers as single galaxies and in an incorrect interpretation of their baryonic properties. Having serendipitously discovered a dust-obscured galaxy merger at $z=1.17$, we aim to determine the baryonic properties of the two merging galaxies, including the star formation rate (SFR) and the stellar, molecular gas and dust masses. Using Band 3 and 6 observations from the Atacama Large Millimeter and submillimeter Array (ALMA) and ancillary data, we studied the morphology of this previously misclassified merger. We deblended the emission, derived the gas masses from CO observations, and modeled the spectral energy distributions to determine the properties of each galaxy. Using the rare combination of ALMA CO(2--1), CO(5--4) and dust-continuum (rest-frame 520mu m) observations, we provide insight into the gas and dust content and into the properties of the interstellar medium of each merger component. We find that only one of the two galaxies is highly obscured by dust, but both are massive ($>10^ M_ and highly star forming (SFR$=60-900 M_ have a moderate-to-short depletion time ($t_ depl <0.7$Gyr) and a high gas fraction ($f_ gas geq1$). These properties can be interpreted as the positive impact of the merger. With this serendipitous discovery, we highlight the power of (sub)millimeter observations to identify and characterise the individual components of obscured galaxy mergers.
Pancreatic ductal adenocarcinoma (PDAC) is a significant cause of cancer-related death globally, and, despite improvements in diagnostics and treatment, survival remains poor. Matrix ...metalloproteinases (MMPs) are enzymes involved in stroma remodelling in inflammation and cancer. MMP-8 plays a varied prognostic role in cancers of the gastrointestinal tract. We examined the prognostic value of MMP-8 immunoexpression in tumour tissue and the amount of MMP-8-positive polymorphonuclear cells (PMNs) in PDAC and their association with immune responses using C-reactive protein (CRP) as a marker of systemic inflammation. Tumour samples from 141 PDAC patients undergoing surgery in 2002−2011 at the Department of Surgery, Helsinki University Hospital were stained immunohistochemically, for which we evaluated MMP-8 expression in cancer cells and the amount of MMP-8-positive PMNs. We assessed survival using the Kaplan−Meier analysis while uni- and multivariable analyses relied on the Cox proportional hazards model. A negative MMP-8 stain and elevated CRP level predicted a poor prognosis (hazard ratio HR = 6.95; 95% confidence interval (CI) 2.69−17.93; p < 0.001) compared to a positive stain and low CRP level (<10 mg/L). The absence of PMNs together with an elevated CRP level also predicted an unfavourable outcome (HR = 3.17; 95% CI 1.60−6.30; p = 0.001). MMP-8 expression in the tumour served as an independent positive prognostic factor (HR = 0.33; 95% CI 0.16−0.68; p = 0.003). Tumour MMP-8 expression and a low CRP level may predict a favourable outcome in PDAC with similar results for MMP-8-positive PMNs and low CRP levels. Tumoural MMP-8 expression represents an independent positive prognostic factor in PDAC.
Context.
Determining when the first galaxies formed remains an outstanding goal of modern observational astronomy. Theory and current stellar population models imply that the first galaxies formed at ...least at
z
= 14 − 15. But to date, only one galaxy at
z
> 13 (GS-z13-0) has been spectroscopically confirmed.
Aims.
The galaxy ‘HD1’ was recently proposed to be a
z
∼ 13.27 galaxy based on its potential Lyman break and tentative O
III
88 μm detection with ALMA. We hereby aim to test this scenario with new ALMA Band 4 observations of what would be the C
II
158 μm emission if HD1 is at
z
∼ 13.27.
Methods.
We carefully analyse the new ALMA Band 4 observations and re-analyse the existing ALMA Band 6 data on the source to determine the proposed redshift.
Results.
We find a tentative 4
σ
feature in the Band 4 data that is spatially offset by 1.″7 and spectrally offset by 190 km s
−1
from the previously reported 3.8
σ
‘O
III
88 μm’ feature. Through various statistical tests, we demonstrate that these tentative features are fully consistent with both being random noise features.
Conclusions.
We conclude that we are more likely to be recovering noise features than both O
III
88 μm and C
II
158 μm emission from a source at
z
∼ 13.27. Although we find no credible evidence of a
z
∼ 13.27 galaxy, we cannot entirely rule out this scenario. Non-detections are also possible for a
z
∼ 13 source with a low interstellar gas-phase metallicity or ionisation parameter and/or high gas density. Moreover, the new continuum and line upper limits provide no strong evidence for or against a lower-redshift scenario. Determining where and exactly what type of galaxy HD1 is, will now likely require JWST/NIRSpec spectroscopy.
We present Atacama Large Millimeter/submillimeter Array (ALMA) 2 mm continuum observations of a complete and unbiased sample of 99 870 mu m selected submillimeter galaxies (SMGs) in the Extended ...Chandra Deep Field South (ALESS). Our observations of each SMG reach average sensitivities of 53 mu Jy beam(-1). We measure the flux densities for 70 sources, for which we obtain a typical 870 mu m-to-2 mm flux ratio of 14 +/- 5. We do not find a redshift dependence of this flux ratio, which would be expected if the dust emission properties of our SMGs were the same at all redshifts. By combining our ALMA measurements with existing Herschel/SPIRE observations, we construct a (biased) subset of 27 galaxies for which the cool dust emission is sufficiently well sampled to obtain precise constraints on their dust properties using simple isothermal models. Thanks to our new 2 mm observations, the dust emissivity index is well constrained and robust against different dust opacity assumptions. The median dust emissivity index of our SMGs is beta similar or equal to 1.9 +/- 0.4, consistent with the emissivity index of dust in the Milky Way and other local and high-redshift galaxies, as well as classical dust-grain model predictions. We also find a negative correlation between the dust temperature and beta, similar to low-redshift observational and theoretical studies. Our results indicate that beta similar or equal to 2 in high-redshift dusty star-forming galaxies, implying little evolution in dust-grain properties between our SMGs and local dusty galaxy samples, and suggesting that these high-mass and high-metallicity galaxies have dust reservoirs driven by grain growth in their interstellar medium.
Galaxy mergers play a critical role in galaxy evolution - altering the size, morphology, dynamics and composition of galaxies. So far, galaxy mergers have mostly been identified through visual ...inspection of their rest-frame optical and NIR emission. But, dust can obscure this emission, resulting in the misclassification of mergers as single galaxies, and the incorrect interpretation of their baryonic properties. Having serendipitously discovered a dust-obscured galaxy merger at z = 1.17, we aim to determine the baryonic properties of the two merging galaxies, including the star formation rate, and stellar, molecular gas, and dust masses. Using Band 3 and 6 observations from the Atacama Large Millimeter and submillimeter Array (ALMA), and ancillary data, we study the morphology of this previously misclassified merger. We deblend the emission, derive the gas masses from CO observations, and model the spectral energy distributions, to determine the properties of each galaxy. Using the rare combination of ALMA CO(2-1), CO(5-4) and dust-continuum (rest-frame 520um) observations, we provide insights into the gas and dust content and ISM properties of each merger component. We find that only one of the two galaxies is highly dust-obscured, whereas both are massive (> 10^10.5 Msun), highly star-forming (SFR = 60-900Msun/yr), have a moderate-to-low depletion time (tdepl < 0.7Gyr) and high gas fraction ( fgas >= 1). These properties can be interpreted as the positive impact of the merger. With this serendipitous discovery, we highlight the power of (sub)millimeter observations to identify and characterise the individual components of obscured galaxy mergers.
The Next Generation Very Large Array (ngVLA) is a planned radio interferometer providing unprecedented sensitivity at wavelengths between 21 cm and 3 mm. Its 263 antenna element array will be ...spatially distributed across North America to enable both superb low surface brightness recovery and sub-milliarcsecond angular resolution imaging. The project was developed by the international astronomy community under the lead of the National Radio Astronomy Observatory (NRAO), and is anticipated to be built between 2027 and 2037. Two workshops have been held in 2022 and 2023 with the goal to discuss and consolidate the scientific interests in the ngVLA within the German astronomical community. This community paper constitutes a collection of 48 science ideas which the German community aims to pursue with the ngVLA in the 2030s. This is not a complete list and the ideas are not developed at the level of a "Science Book", such that the present document is mainly meant provide a basis for further discussion within the community. As such, additional contributions are welcome, and will be considered for inclusion in future revisions.
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